.NET FOLLOWER

    In our SharePoint 2007 application, there was a custom upload page for a document library. The custom upload page was derived from the Microsoft.SharePoint.ApplicationPages.UploadPage defined in the Microsoft.SharePoint.ApplicationPages.dll. Within application web pages, all links to the upload page were direct, while the page itself was located in the _layouts folder. After migration to the SharePoint 2010, I’ve found out that every request to the custom upload page is transferred to the Uploadex.aspx (located in the _layouts folder as well): the URL in browser corresponds to our upload page, but the content corresponds to the Uploadex.aspx. After a short investigation by means of .Net Reflector I found the reason in the UploadPage base class defined in Microsoft.SharePoint.ApplicationPages.dll, Version=14.0.0.0. Let’s take a look at the OnPreInit method of the UploadPage:

protected override void OnPreInit(EventArgs e)
{
    if (!this.customPage)
    {
        string customUploadPage = base.Web.CustomUploadPage;
        if (!string.IsNullOrEmpty(customUploadPage))
        {
            try
            {
                base.Server.Transfer(customUploadPage);
            }
            catch (Exception)
            {
            }
        }
    }
    base.OnPreInit(e);
}

*Note: this code was added in SharePoint 2010 and wasn’t presented in SharePoint 2007

As we can see, the SharePoint 2010 itself allows to define the CustomUploadPage for a website. If it’s defined, the UploadPage automatically transfers every request to it. Apparently, after migration the CustomUploadPage was somehow set to _layouts/Uploadex.aspx. Another interesting moment here is the customPage boolean field, which acts as marker indicating whether the current page is the custom upload page or not.

Probably, the acceptable solution for our issue would be to set the CustomUploadPage property of the SPWeb object to the URL of our own custom upload page. But, firstly, the problem here is that our upload page derived from the UploadPage doesn’t know that it’s a custom one as the customPage field is set to false by default. Thus, without any code modification, we will have a kind of loop here, because our custom page due to the UploadPage base class will be transferring the request to itself infinitely. Secondly, I don’t want to rely on the CustomUploadPage property, which can be unexpectedly changed. I just want when I click on the direct link to our upload page, this page would be opened without any sudden redirections and transfers.

So, the best solution is to set the customPage field to true within the constructor of our custom upload page. No transfer happens in this case, and we don’t need to deal with the CustomUploadPage at all. In our case It looks like:

public class MyUploadPage : UploadPage
{
    // ...
    public MyUploadPage()
    {
        customPage = true;
    }
    // ...
}

That’s all!

    I was asked to develop a control based on the ItemPicker control, which, in addition to ability of choosing an external data item through BDC, brings it to client side without page postback. There was the following supposed sequence of actions:

1. An user chooses a data item in the Picker Dialog;
2. The identifier of the selected item is sent to the server through an Ajax-like technology;
3. Using the received identifier, the server fetches the proper data out through BDC and sends it back to the client. By “the proper data” I mean the values of either all fields available in the selected data item or only fields defined in control declaration;
4. On the client side, the received data is parsed and displayed in UI;

Additionally, the control should be free of bindings to SPField as it should be capable to reside within an independent aspx-page locating in the _layout folder.

*Note: for better understanding of BDC infrastructure, please read the following blog posts: SharePoint: Brief introduction to Business Data Catalog and SharePoint: Understanding BusinessData Column.

So, I developed the required control and made it as reusable as possible. Let’s call the control MyItemPicker (it’s so unusual, isn’t? :)). For sake of simplicity I decided to use the ASP.Net client callbacks applied through the ICallbackEventHandler interface. The ASP.Net client callbacks can be considered as a wrapper on XMLHTTP object. Also the MyItemPicker comprises and uses the standard ItemPicker.

Ok, let’s start with declaration of the control within page:

<MYCC:MyItemPicker id="myItemPicker" runat="server" LobSystemInstanceName="Products" 
EntityName="Product" PrimaryColumnName="Name" ClientCallback="MyClientCallback" 
ClientCallbackError="MyClientCallbackError" CallbackBDCFieldFilter="Price,Producer" />

The significant properties here are

• LobSystemInstanceName is the name of the Lob System Instance, through which data is provided to pick;
• EntityName is the type name of data items populating the picker;
• PrimaryColumnName is the name of the data item field, the value of which is used as a display value;
• ClientCallback is the name of the JavaScript function, which has to be present within the page. In case of success, the given function accepts and processes the server response containing fetched data;
• ClientCallbackError is the name of the JavaScript function, which can be within the page and is called, when server fails to fulfill request. This property is optional;
• CallbackBDCFieldFilter is the comma-separated string containing names of data item fields that should be included in server response. For example, if a BDC Entity has four fields – ID, Name, Price and Producer, you might want to have on client side only two of them – Price and Producer. If the CallbackBDCFieldFilter property is empty or not presented in the declaration, server response contains the values of all available fields of BDC Entity;

The sample of the JavaScript functions, which should be indicated in the ClientCallback and ClientCallbackError properties, is shown below. Note the functions’ signatures.

<script type="text/javascript">

    function MyClientCallback(result, context) {

        alert("Result: " + result);
        
        if (result != null && typeof result != "undefined" && result.length != 0) {
            var res = eval("(" + result + ")");

            alert('Price: '    + res.Price);
            alert('Producer: ' + res.Producer);
            
            // update UI with received data
        }        
    }

    function MyClientCallbackError(result, context) {
        alert('Error: ' + result);            
    }

</script>

The server response looks like

{ 'Price' : '10.00', 
  'Producer' : 'Microsoft Corporation' }

Thus, the response is formatted in the manner to be easily turned into JavaScript object by means of the eval function.

So, it’s time to examine the source code of the MyItemPicker itself.

using System;
using System.Collections.Generic;
using System.Text;
using Microsoft.SharePoint;
using Microsoft.SharePoint.Portal.WebControls;
using System.Web.UI;
using Microsoft.Office.Server.ApplicationRegistry.Infrastructure;
using Microsoft.Office.Server.ApplicationRegistry.MetadataModel;
using Microsoft.Office.Server.ApplicationRegistry.Runtime;
using System.Data;

namespace MyControls
{
    public class MyItemPicker : Control, ICallbackEventHandler
    {
        #region fields & properties
        protected ItemPicker _picker                    = null;
        protected string     _callbackRequestedEntityId = string.Empty;

        public string LobSystemInstanceName  { get; set; }
        public string EntityName             { get; set; }
        public string PrimaryColumnName      { get; set; }

        public string ClientCallback         { get; set; }
        public string ClientCallbackError    { get; set; }

        public string CallbackBDCFieldFilter { get; set; }
        #endregion

        #region public methods
        // Implementation of the ICallbackEventHandler interface
        // Generates response that will be sent to client
        public string GetCallbackResult()
        {
            return GetJSResult();
        }
        // Implementation of the ICallbackEventHandler interface
        // Retrieves and preserves identifier of selected data item sent from client
        public void RaiseCallbackEvent(string eventArgument)
        {
            _callbackRequestedEntityId = eventArgument;
        }
        #endregion

        #region internal methods
        protected override void OnInit(EventArgs e)
        {
            base.OnInit(e);
            EnsureChildControls();            
        }

        protected override void CreateChildControls()
        {            
            base.CreateChildControls();

            if (_picker == null)
            {
                _picker = new ItemPicker();                
                _picker.MultiSelect = false;
                _picker.ID = ID + "_ItemPicker";
                try
                {
                    this.SetExtendedDataOnPicker(_picker);
                }
                catch (Exception exception)
                {
                    _picker.ErrorMessage = exception.Message;
                    _picker.Enabled = false;
                }

                this.Controls.Add(_picker);
            }            
        }

	/// <summary>
        /// Initilizes main item picker's properties
        /// </summary>        
        protected virtual void SetExtendedDataOnPicker(ItemPicker picker)
        {            
            ItemPickerExtendedData data = new ItemPickerExtendedData();

            BDCMetaRequest request = new BDCMetaRequest(LobSystemInstanceName, EntityName);
            data.SystemInstanceId  = request.FoundLobSystemInstance.Id;
            data.EntityId          = request.FoundEntity.Id;

            List<uint> list = new List<uint>();
            FieldCollection fields = request.FoundEntity.GetSpecificFinderView().Fields;
            foreach (Field field in fields)
                if (string.Equals(field.Name, PrimaryColumnName, StringComparison.OrdinalIgnoreCase))                
                    data.PrimaryColumnId = field.TypeDescriptor.Id;
                else
                    list.Add(field.TypeDescriptor.Id);

            data.SecondaryColumnsIds = list.ToArray();
            picker.ExtendedData = data;
        }

        protected override void OnPreRender(EventArgs e)
        {
            base.OnPreRender(e);
            AddJSCallbackFunctions();
            AddAdditionalJSFunctions();
        }

        /// <summary>
        /// Generates and adds auxiliary JavaScript functions to the page
        /// </summary> 
        protected void AddAdditionalJSFunctions()
        {
            if (_picker != null)
            {
                _picker.LoadPostData(null, null); // this line is required to force CreateChildControls() and to have HiddenEntityKey created
                Control upLevelDiv = FindControlRecursive(_picker, "upLevelDiv");
                if (upLevelDiv != null)
                {
                    string clearFuncName = "ClearItemPicker_" + ID;
                    string clearFunc =
                        "function " + clearFuncName + "() {" +
                            "var upLevelDiv = document.getElementById('" + upLevelDiv.ClientID + "');" +
                            "if (upLevelDiv != null) {" +
                                "upLevelDiv.innerHTML = '';" +
                                "updateControlValue('" + _picker.ClientID + "');" +
                                "}" +
                            "}";
                    Page.ClientScript.RegisterClientScriptBlock(GetType(), clearFuncName, clearFunc, true);
                }
                
                Control hiddenEntityDisplayTextControl = FindControlRecursive(_picker, "HiddenEntityDisplayText");
                if (hiddenEntityDisplayTextControl != null)
                {
                    string getDisplayTextFuncName = "GetDisplayText_" + ID;
                    string getDisplayTextFunc =
                        "function " + getDisplayTextFuncName + "() {" +
                            "var hiddenEntityDisplayTextControl = document.getElementById('" + hiddenEntityDisplayTextControl.ClientID + "');" +
                            "return hiddenEntityDisplayTextControl != null ? hiddenEntityDisplayTextControl.value : '';" +
                        "}";
                    Page.ClientScript.RegisterClientScriptBlock(GetType(), getDisplayTextFuncName, getDisplayTextFunc, true);
                }
            }            
        }

        /// <summary>
        /// Generates and adds the picker's AfterCallbackClientScript to the page
        /// </summary> 
        protected void AddJSCallbackFunctions()
        {
            if (_picker != null)
            {
                string callbackFunc = null;
                if (!string.IsNullOrEmpty(ClientCallback) && !string.IsNullOrEmpty(ClientCallbackError))
                    callbackFunc = Page.ClientScript.GetCallbackEventReference(this, "arg", ClientCallback, "context", ClientCallbackError, true);
                else
                {
                    if (!string.IsNullOrEmpty(ClientCallback))
                        callbackFunc = Page.ClientScript.GetCallbackEventReference(this, "arg", ClientCallback, "context", true);
                }
                if (!string.IsNullOrEmpty(callbackFunc))
                {
                    _picker.LoadPostData(null, null); // this line is required to force CreateChildControls() and to have HiddenEntityKey created

                    Control pickerEntityKeyHidden = FindControlRecursive(_picker, "HiddenEntityKey");
                    if (pickerEntityKeyHidden != null)
                    {
                        string clientFuncName = "GetBdcFieldValuesAsync_" + ID;
                        string clientFunc =
                            "function " + clientFuncName + "(context)" +
                            "{" +
                                "var pickerEntityKeyHidden = document.getElementById('" + pickerEntityKeyHidden.ClientID + "');" +
                                "if (pickerEntityKeyHidden != null)" +
                                "{" +
                                    "var arg = pickerEntityKeyHidden.value;" +
                                    callbackFunc + ";" +
                                "}" +
                            "}";
                        Page.ClientScript.RegisterClientScriptBlock(GetType(), clientFuncName, clientFunc, true);
                        _picker.AfterCallbackClientScript = clientFuncName + "('" + ID + "');";
                    }
                }
            }
        }

        /// <summary>
        /// Makes request to external data source and returns json-result
        /// </summary>         
        protected string GetJSResult()
        {
            string res = string.Empty;

            try
            {
                if (!string.IsNullOrEmpty(_callbackRequestedEntityId))
                {
                    Dictionary<string, byte> bdcFieldFilter = GetBDCFieldFilter(CallbackBDCFieldFilter);
                    
                    BDCRequestById request = new BDCRequestById(LobSystemInstanceName, EntityName, _callbackRequestedEntityId);

                    StringBuilder sb = new StringBuilder();
                    sb.Append("{");
                    foreach (Field field in request.FoundEntityInstance.ViewDefinition.Fields)
                    {
                        if (bdcFieldFilter.Count == 0 || bdcFieldFilter.ContainsKey(field.Name))
                        {
                            if (sb.Length > 1)
                                sb.Append(", ").AppendLine();
                            sb.Append("'").Append(field.Name).Append("' : ");
                            sb.Append("'").Append(Convert.ToString(request.FoundEntityInstance.GetFormatted(field))).Append("'");
                        }
                    }
                    sb.Append("}");                    

                    res = sb.ToString();
                }
            }
            catch (Exception ex)
            {
                // write error to log
            }

            return res;
        }

        /// <summary>
        /// Parses the user defined list of bdc fields, the values of which should be retrieved
        /// </summary>        
        protected static Dictionary<string, byte> GetBDCFieldFilter(string commaSeparatedBdcFields)
        {
            Dictionary<string, byte> res = new Dictionary<string, byte>(StringComparer.OrdinalIgnoreCase);

            if (!string.IsNullOrEmpty(commaSeparatedBdcFields))
            {
                string[] bdcFields = commaSeparatedBdcFields.Split(new string[] { "," }, StringSplitOptions.RemoveEmptyEntries);
                foreach (string field in bdcFields)
                    res.Add(field, 0);
            }

            return res;
        }
        #endregion
    }
}

You probably noticed that the functions AddJSCallbackFunctions and AddAdditionalJSFunctions generate and add some JavaScript functions to the page. The exact names of these JavaScript functions depend on the id attribute defined in control declaration. For example, if control id is “myItemPicker“, the functions’ name will be GetBdcFieldValuesAsync_myItemPicker, ClearItemPicker_myItemPicker and GetDisplayText_myItemPicker.

Let’s take a look at the functions. The main function is GetBdcFieldValuesAsync_myItemPicker, which extracts the encoded id of selected item from ItemPicker and then makes the Ajax-like client callback to the server. The rest two functions are auxiliary, they are not used by MyItemPicker directly, but they are very useful for developing an interaction between user and MyItemPicker. As their names imply, the ClearItemPicker_myItemPicker clears the ItemPicker, and the GetDisplayText_myItemPicker returns the text displayed to user in ItemPicker. The listing below demonstrates the functions within page:

<script type="text/javascript">

    function GetBdcFieldValuesAsync_myItemPicker(context) {
        var pickerEntityKeyHidden = document.getElementById('myItemPicker_ItemPicker_HiddenEntityKey');
        if (pickerEntityKeyHidden != null) {
            var arg = pickerEntityKeyHidden.value;
            WebForm_DoCallback('myItemPicker', arg, ClientCallback, context, ClientCallbackError, true);
        }
    }

    function ClearItemPicker_myItemPicker() {
        var upLevelDiv = document.getElementById('myItemPicker_ItemPicker_upLevelDiv');
        if (upLevelDiv != null) {
            upLevelDiv.innerHTML = '';
            updateControlValue('myItemPicker_ItemPicker');
        }
    }

    function GetDisplayText_myItemPicker() {
        var hiddenEntityDisplayTextControl = document.getElementById('myItemPicker_ItemPicker_HiddenEntityDisplayText');
        return hiddenEntityDisplayTextControl != null ? hiddenEntityDisplayTextControl.value : '';
    }
</script>

The SetExtendedDataOnPicker and GetJSResult methods of MyItemPicker employ the classes BDCMetaRequest and BDCRequestById that are described in my post SharePoint: How to get value from BDC.

The FindControlRecursive method is mentioned in another my post.

    To get the directory path, which SharePoint was installed into, the SPUtility.GetGenericSetupPath method can be used. MSDN says the method returns the full local path for the specified subdirectory. It’s supposed, you pass a relative path of the subdirectory being located inside the SP installation directory. Getting exactly the SP installation directory path, just pass an empty string to the method.

...
using Microsoft.SharePoint.Utilities;
...
string spInstDirPath = SPUtility.GetGenericSetupPath(string.Empty);

In my case the above code sample returns C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\14 for SharePoint 2010 and C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\12 for SharePoint 2007. To get the path of the Features directory, use the following code snippet:

string spFeaturesDirPath = SPUtility.GetGenericSetupPath(@"template\features");

The GetGenericSetupPath method is accessible only if an application has reference to Microsoft.SharePoint.dll. Let’s assume we develop a SharePoint independent application. How can we get the SP installation directory path in this case? Having analyzed the GetGenericSetupPath method using .Net Reflector, I’ve disclosed that the directory path we are interested in is read from Windows Registry. The SharePoint independent method to get the SP installation directory path and an accompanying method are presented below:

using System;
using System.IO;
using Microsoft.Win32;

...

public static T GetLocalMachineRegistryValue<T>(string path, string valueName, T defaultValue)
{            
    T res = defaultValue;
    try
    {
        using (RegistryKey key = Registry.LocalMachine.OpenSubKey(path))
        {
            if (key != null)
            {
                object valObj = key.GetValue(valueName);
                if (valObj is T)
                    res = (T)valObj;
            }
        }
    }
    catch (Exception)
    {
        // write to log
    }            
    return res;
}

public static string GetSPInstallationDirectoryPath()
{
    const string keyVer2007 = @"SOFTWARE\Microsoft\Shared Tools\Web Server Extensions\12.0";
    const string keyVer2010 = @"SOFTWARE\Microsoft\Shared Tools\Web Server Extensions\14.0";            
    const string valueName  = "Location";

    string res = GetLocalMachineRegistryValue<string>(keyVer2010, valueName, null);

    if(res == null)
        res = GetLocalMachineRegistryValue<string>(keyVer2007, valueName, null);

    return res;
}

The following method is dedicated to get the path of the Features directory:

public static string GetSPFeaturesDirectoryPath()
{
    const string featuresDirPathPattern = @"template\features";

    string res = null;

    string instDirPath = GetSPInstallationDirectoryPath();
    if (instDirPath != null)
        res = Path.Combine(instDirPath, featuresDirPathPattern);

    return res;
}

Here is how you can use these methods:

string spInstallationDir = GetSPInstallationDirectoryPath();
string spFeaturesDir     = GetSPFeaturesDirectoryPath();

Please note, when accessing Registry on x64 Windows from a x32 application, you may stumble upon Registry Reflection and Registry Redirector. Please, take a look at the article to read from the right Registry Key.

Related posts:

• SharePoint: The usage of SPUtility.GetLocalizedString

    If an unexpected error occurs on a SharePoint environment, by default, you get a meaningless error message as the following: An unexpected error has occurred. Despite the given error message is considered as friendly one for users, we as developers want to have more information to detect the reason. SharePoint is built on ASP.Net technology, it means we can enable the detailed error message and, in addition, displaying of call-stack by changing some settings in a web.config file. We need to find the node customErrors and change its mode to “Off”, which specifies that custom errors are disabled and the detailed errors are shown to the local and remote clients. Then we need to find the node SafeMode and change its CallStack to “true”. CallStack attribute defines whether a call-stack and an exception message are displayed when a system-level exception takes place while ASP.NET processes a request from the local and remote clients. The last step is to save the made changes. The nodes we are interested in are shown below:

Before:

<customErrors mode="On" />
<SafeMode MaxControls="200" CallStack="false" ... >

After:

<customErrors mode="Off" />
<SafeMode MaxControls="200" CallStack="true" ... >

The required web.config file containing main settings locates in \inetpub\wwwroot\wss\VirtualDirectories\<SHAREPOINT APP PORT NUMBER>. For SharePoint 2007 it’s usually enough to make changes in the given file only. As for SharePoint 2010, the changes also should be applied to a number of additional web.config files in 14 hive (\Program Files\Common Files\Microsoft Shared\Web Server Extensions\14) of SharePoint 2010. If you make a search for web.config inside the 14 folder you likely will find more than 30 different files. I recommend firstly to make changes in web.config files locating in \14\TEMPLATE\ADMIN and \14\TEMPLATE\LAYOUTS and then check whether you still get not detailed error message. If so, continue making the changes file by file until the message will get more detailed.

Related posts:

• SharePoint: How to Restore a SharePoint Site from a Database Backup
• SharePoint: The specified SPContentDatabase has been upgraded to a newer version
• SharePoint: How to shrink transaction log file

    Deploying a .wsp-file on SharePoint 2010, you may stumble over the next error message:
Install-SPSolution : Admin SVC must be running in order to create deployment timer job.

How have I got it? In SharePoint 2010 Management Shell I had successfully performed the following command to upload my SP2010 solution package into the system:

Add-SPSolution "C:\WSPDeployment\My2010Solution.wsp"

Then I had tried to run the next one to deploy the uploaded solution:

Install-SPSolution -Identity My2010Solution.wsp -GACDeployment -AllWebApplications

and after that I received the mentioned error.

Now, how to fix it. It’s needed to go to Administrative Tools -> Services and manually start the service called SharePoint 2010 Administration. Not to have such error in the future, change service’s Startup type to Automatic.

Having made this, I run Install-SPSolution once again and received a new error:
A deployment or retraction is already under way for the solution “My2010Solution.wsp”, and only one deployment or retraction at a time is supported.

It looked like an appropriate deployment job was added to the list of timer jobs, but the attempt to execute the job failed due to unstarted SharePoint 2010 Administration service. I found a solution here. We need to cancel the deployment job by performing the next steps:

1. Grab the id of the job by running the command: stsadm -o enumdeployments. Yep, the old friend, stsadm helps us out 🙂 Look through the result, find the required deployment job and grab the id. The result should look like

   C:\...red\Web Server Extensions\14\BIN>stsadm -o enumdeployments
   
   <Deployments Count="1">
      <Deployment JobId="2de92a5f-6c70-4325-ac2c-293a34dd9c67">
         <Title>Microsoft SharePoint Foundation Solution Deployment for "My2010Solution.wsp"</Title>
         <Type>Deployment</Type>
         <State>Pending</State>
         <Schedule>12/16/2011 3:47 PM</Schedule>
         <File>My2010Solution.wsp</File>
         <ServerType>Front-end Web server</ServerType>
         <Target>http://mySPServer/</Target>
      </Deployment>
   </Deployments>
   

2. Using the found id, cancel the job by means of the command stsadm-o canceldeployment-id “found Job id”. For example, in my case it’s

   stsadm -o canceldeployment -id "2de92a5f-6c70-4325-ac2c-293a34dd9c67"

   If it succeed you get “Operation completed successfully” message.

3. Run again stsadm -o enumdeployments to make sure that the given deployment job disappeared

Ok, now you can repeat deployment of your solution, run Install-SPSolution again. The issues was overcome in my case.