How can i call method from usercontrol from another usercontrol using asp.net?

Question

I have two usercontrols: UserControl1 and UserControl2, these controls are added in the Page.aspx.

UserControl1: This usercontrol contains method for hidden textboxes in this usercontrol. This method is called "HideTextbox"

UserControl2: I want to call method "HideTextBox" from UserControl2.

How can I call method HideTextBox from UserControl2 ?

Answer 1

Only if both are usercontrols or servercontrols, or you're looking for a servercontrol from a usercontrol will this work. (not from a servercontrol because you can't get a reference to the asp.usercontrol_xx assembly)

First get a reference to the parent page (usually this can be done with this.Parent. Next do a recursive FindControl on the parent to find a control whose type is UserControl2. Example code:

//this for extension method
public static UserControl2 FindUserControl2Recursive(this Control root)
{
    var uc2 = root as ASP.UserControls_UserControl2_ascx;
    if (uc2 != null)
    {
        return uc2;
    }
    foreach (var control in root.Controls)
    {
        uc2 = control.FindUserControl2Recursive();
        if (uc2 != null)
        {
            return uc2;
        }
    }
    return null;
}

Once you have your Usercontrol2 reference, you can easily call your public method.

Answer 2

This problem can be solved by creating a custom event in UC2 and consuming that event on the main page to invoke the hide method on UC1.

You declare a delegate in your user control

public delegate void HideTextBoxEventHandler(object sender, EventArgs e);

Then define the event for the delegate you created

public event HideTextBoxEventHandler HideTextBox;

At the point in the code where you want to hide text box you need to invoke that event:

if (this.HideTextBox != null) // if there is no event handler then it will be null and invoking it will throw an error.
{
   EventArgs e = new EventArgs();
   this.HideTextBox(this, e);
}

Then from the main page create an event handling method

protected void UserControl2_HideTextBox(Object sender, EventArgs e)
{
   UC1.InvokeHideTextBox();  // this is the code in UC1 that does the hiding
}

You will need to add to the page load or where ever you are loading UC2

UC2.HideTextBox += new UserControl2.HideTextBoxEventHandler(this.UserControl2_HideTextBox);

Answer 3

I would declare interface on control that knows how to hide text boxes, something like this :

public interface ITextBoxHider
{
  void HideTextBoxes();
}

after that implement this interface on UserControl1, when you want to hide text boxes enumerate all controls on a form and find one that implements ITextBoxHider, and then simply call that method :

helper method that will enumerate all controls :

public static IEnumerable<Control> GetAllChildren(Control parent)
{
  foreach (Control control in parent.Controls)
  {
    foreach (Control grandChild in GetAllChildren(control))
        yield return grandChild;

    yield return control;
  }
}

using that method and calling HideTextBoxes from UserControl2 :

var hider = GetAllChildren(this.Page).FirstOrDefault(ct => ct is ITextBoxHider);
if (hider != null)
  (hider as ITextBoxHider).HideTextBoxes();