Question

I have a master page, there’s only one menu item and a contentplaceholder there. I have another web form that inherits form this master page. As nor mal I’ve put all my controls in the contentplaceholder. On my form’s Page_Load event I want to set Enabled=false of all the dropdownlist controls. For this purpose I write:

       foreach (Control control in Page.Controls)
    {
        if (control is DropDownList)
        {
            DropDownList ddl = (DropDownList)control;
            ddl.Enabled = false;
        }
    }

But all the dropdownlists remain Enabled. When I check for the count of the Page.Control I see only one control and it’s the menuitem of the form’s masterpage. What should I do to get the list of controls that are in my current form?

Answer 1

your foreach loop will not work as your control can have child control and they can also have child control and then DDL.

What I’ll prefer is to create a list of controls first then iterate through that list which is filled with your desire DDL controls.

public void FindTheControls(List<Control> foundSofar, Control parent) 
{
  foreach(var c in parent.Controls) 
  {
    if(c is IControl) //Or whatever that is you checking for 
    {
       if (c is DropDownList){ foundSofar.Add(c); } continue;

       if(c.Controls.Count > 0) 
       {
           this.FindTheControls(foundSofar, c);
       }
     }
  }  
}

Later you can directly loop through foundSofar and it is sure that it will contain all DDL controls inside it.