How to access Page Controls value from C# webmethod

Question

I'm using C# asp.net web form application. I am using asp grid view control with this pages. Once i add some ajax method with C# web method to capture some data in web page. In this C# web method I can't capture grid view records. It's shows null always. How can I get this records in web method.

This is my Code:

[WebMethod]
public bool ValidateGrid(string RowIndex, string CellIndex)
{

   HomeDefault pageMethods = new HomeDefault();
   pageMethods.ValidateGridViewControls(Convert.ToInt32(RowIndex), Convert.ToInt32(CellIndex));
   return true;
 }


private void ValidateGridViewControls(int RowIndex, int CellIndex)
{
    foreach (GridViewRow row in grvProgram.Rows)
    {

    }
}

in this case grvProgram.Rows is alaways null.

please help me to sort out this issue,

Answer 1

There are two issues you are going to experience with your current implementation:

1) as Zaki pointed out in comments, the [WebMethod] should be

public static bool ValidateGrid(string RowIndex, string CellIndex)

2) I get the suspicion that HomeDefault pageMethods = new HomeDefault(); is your aspx page code-behind class. When asp.net creates a HomeDefault class, it does not only call new HomeDefault(). In fact, it does lots of crazy magical things to it so that the class will have access to the HttpContext, as well as postback information if any exists. This is why when you call

yourPage.grvProgram.property

grvProgram is null. It is because the constructor of that class does not make it, asp.net makes it through other methods like InitializeComponent, etc. DO NOT call those methods yourself, they may have unintended side effects or dependencies in .net or the IIS pipeline.

How to solve this then?

Look at how your grvProgram control is made. It must put data in there somewhere, and then create the rows using that data. Instead of comparing user input with your control, compare with the data that is used to populate the control.

Yes, this is more work in the sense that you will have to refactor the logic for retrieving and populating your control, but it is also much safer and faster because you will not be relying on the state of an entire code-behind class to do data validation.