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Archive for August, 2012

ASP.NET: How to trigger a validator on the client-side

August 27th, 2012 Admin No comments


ValidatorValidate

The easiest way to trigger a validator on the client-side is to use the ValidatorValidate method provided by ASP.NET as a part of a Validation client-side API. You don’t need to include any js-files so as the all required scripts will be included automatically when you add a validator to your page. The typical use is something like this

var validator = document.getElementById('ctl00_PlaceHolderMain_info_textbox').Validators[0]; // Page_Validators[0];

ValidatorValidate(validator); // fire validation
ValidatorUpdateIsValid(); // update the global Page_IsValid flag

The ValidatorValidate makes the passed validator examine the input element bound to it and updates the validator‘s display (shows or hides its error message). I also recommend to call the ValidatorUpdateIsValid method, which updates the global variable Page_IsValid and by that may prevent the Html-form submit when the validator failed.

Below is a simple JavaScript function I use to force validation of a specified input. The function gets the input by the passed id, then goes through the all validators linked to the input and activates each of them. Finally, it updates the global Page_IsValid flag.

function ForceInputValidation(inputId) {
    var targetedControl = document.getElementById(inputId);    

    if (typeof(targetedControl.Validators) != "undefined") {
        var i;
        for (i = 0; i < targetedControl.Validators.length; i++)
            ValidatorValidate(targetedControl.Validators[i]);
    }

    ValidatorUpdateIsValid();
}

ASP.Net places the initialization of validators at the end of the web page, so, it makes sense to handle the input‘s Validators-collection after the page has been loaded entirely. The following example demonstrates how to fire validation of the specified input right after the page has been loaded. jQuery is a best helper in that.

$(document).ready(function () {
    ForceInputValidation('ctl00_PlaceHolderMain_info_textbox');
});


ValidatorEnable

As some blogs and forums recommend, you can also use another built-in function – ValidatorEnable, the code of which is shown below:

function ValidatorEnable(validator, enable) {
    validator.enabled = (enable != false);
    ValidatorValidate(validator);
    ValidatorUpdateIsValid();
}
// ...
// the typical use to fire validation is
var validator = document.getElementById('ctl00_PlaceHolderMain_info_textbox').Validators[0]; // Page_Validators[0];
ValidatorEnable(validator, true);

The ValidatorEnable calls sequentially the same ValidatorValidate and ValidatorUpdateIsValid functions we use above. Thus to activate one validator you can use, with no difference, either ValidatorEnable or combination of ValidatorValidate and ValidatorUpdateIsValid. But activating several validators (like in ForceInputValidation function) I advise employing the pair of the ValidatorValidate and ValidatorUpdateIsValid functions. That is because the ValidatorUpdateIsValid loops through all validators on the page. So, for best performance we should fire the all required validators and then call ValidatorUpdateIsValid once.

ps here is good source of information about the client-side validation.

SharePoint: How to pass parameters into a Modal Dialog Window and then access them

August 3rd, 2012 Admin 2 comments


Passing parameters into a Modal Dialog Window

Opening a web page in a Modal Dialog Window we can pass parameters to it through the args property of dialog options. A typical JavaScript might look like

function OpenDialog() {
  var opt = {
    url     : 'somePage.aspx',
    autoSize: true,

    /* additional parameters */
    args: { arg1: 'The second argument is ', arg2: 12345 },

    dialogReturnValueCallback:
      function (res, retVal) {
        if (res === SP.UI.DialogResult.OK) { /* do something */ }
        else { /* do something else */ }
      }
  };
  SP.UI.ModalDialog.showModalDialog(opt);
}

Now let’s take a look how these parameters can be accessed from within the Parent-page and the page opened in the dialog.


Accessing the arguments from within the page opened in the dialog

In general case, when opening a SharePoint-based page, the passed arguments could be reached using a script similar to the following:

function DoSomethingWithArgs() {
  var passedArgs = SP.UI.ModalDialog.get_childDialog().get_args(); /* get access to the passed parameters */
  alert(passedArgs.arg1 + passedArgs.arg2);
}

The key method here is SP.UI.ModalDialog.get_childDialog, which allows to get the current dialog, or, to be more precise, the current SP.UI.Dialog object. The retrieved object, in turn, exposes the get_args method to access the passed parameters.

A possible use of the DoSomethingWithArgs function from the sample above is

<a href="#"
  onclick="ExecuteOrDelayUntilScriptLoaded(DoSomethingWithArgs, 'sp.ui.dialog.js'); return false;">
Show me the passed arguments
</a>

In case the web page opened in the dialog knows nothing about SharePoint and doesn’t include appropriate SharePoint JavaScript files, use the following version of the code:

function DoSomethingWithArgs() {
  var passedArgs = window.frameElement.dialogArgs; /* get access to the passed parameters */
  alert(passedArgs.arg1 + passedArgs.arg2);
}

Where the dialogArgs as a property of the window.frameElement object is provided by SP Dialog framework and returns the passed arguments.

Assuming the SharePoint‘s ExecuteOrDelayUntilScriptLoaded function isn’t available as well, the possible use of the DoSomethingWithArgs is quite straightforward:

<a href="#" onclick="DoSomethingWithArgs(); return false;">
Show me the passed arguments
</a>

All other conditions being equal, I recommend the approach with the window.frameElement object as it works always and doesn’t require the page in the dialog to be bound to SharePoint somehow.


Accessing the passed arguments from within the Parent-page

The Parent-page is a place where we define parameters and pass them to the dialog. So, the most direct way is to store the required values into some variable(s) to access them later. Another way is to rely on Dialog framework and use the code already mentioned in the previous section, namely

//...
var passedArgs = SP.UI.ModalDialog.get_childDialog().get_args();
//...

The more interesting case, however, is to access the passed arguments inside the dialogReturnValueCallback function. The listing below contains an example of one of such dialogReturnValueCallback definitions:

function OpenDialog() {
  var opt = {
    url     : 'somePage.aspx',
    autoSize: true,

    /* additional parameters */
    args: { arg1: 'The second argument is ', arg2: 12345 }, 

    dialogReturnValueCallback:
      function (res, retVal) {
        if (res === SP.UI.DialogResult.OK) {
          var passedArgs = this.get_args(); /* get access to the passed parameters */
          alert(passedArgs.arg1 + passedArgs.arg2);
        }
      }
  };
  SP.UI.ModalDialog.showModalDialog(opt);
}

The dialogReturnValueCallback function will be called in the context of the SP.UI.Dialog object associated with the current Modal Dialog Window. Therefore, inside the function the passed arguments can be accessed using this-keyword.

A possible use of the OpenDialog is shown below:

<a href="#"
  onclick="ExecuteOrDelayUntilScriptLoaded(OpenDialog, 'sp.ui.dialog.js'); return false;">
Open Modal Dialog Window
</a>

ps There is a quite detailed article about dealing with Dialogs in SharePoint 2010. So, read to learn more about Dialog framework.