Better way to find control in ASP.NET

Question

I have a complex asp.net form,having even 50 to 60 fields in one form like there is Multiview, inside MultiView I have a GridView, and inside GridView I have several CheckBoxes.

Currently I am using chaining of the FindControl() method and retrieving the child ID.

Now, my question is that is there any other way/solution to find the nested control in ASP.NET.

Answer 1

FindControl does not search within nested controls recursively. It does only find controls that's NamigContainer is the Control on that you are calling FindControl.

Theres a reason that ASP.Net does not look into your nested controls recursively by default:

• Performance
• Avoiding errors
• Reusability

Consider you want to encapsulate your GridViews, Formviews, UserControls etc. inside of other UserControls for reusability reasons. If you would have implemented all logic in your page and accessed these controls with recursive loops, it'll very difficult to refactor that. If you have implemented your logic and access methods via the event-handlers(f.e. RowDataBound of GridView), it'll be much simpler and less error-prone.

Answer 2

Recursively find all controls matching the specified predicate (do not include root Control):

    public static IEnumerable<Control> FindControlsRecursive(this Control control, Func<Control, bool> predicate)
    {
        var results = new List<Control>();

        foreach (Control child in control.Controls)
        {
            if (predicate(child))
            {
                results.Add(child);
            }
            results.AddRange(child.FindControlsRecursive(predicate));
        }

        return results;
    }

Usage:

myControl.FindControlsRecursive(c => c.ID == "findThisID");

Answer 3

All the highlighted solutions are using recursion (which is performance costly). Here is cleaner way without recursion:

public T GetControlByType<T>(Control root, Func<T, bool> predicate = null) where T : Control {
  if (root == null) {
    throw new ArgumentNullException("root");
  }

  var stack = new Stack<Control>(new Control[] { root });

  while (stack.Count > 0) {
    var control = stack.Pop();
    T match = control as T;

    if (match != null && (predicate == null || predicate(match))) {
      return match;
    }

    foreach (Control childControl in control.Controls) {
      stack.Push(childControl);
    }
  }

  return default(T);
}

Answer 4

I decided to just build controls dictionaries. Harder to maintain, might run faster than the recursive FindControl().

protected void Page_Load(object sender, EventArgs e)
{
  this.BuildControlDics();
}

private void BuildControlDics()
{
  _Divs = new Dictionary<MyEnum, HtmlContainerControl>();
  _Divs.Add(MyEnum.One, this.divOne);
  _Divs.Add(MyEnum.Two, this.divTwo);
  _Divs.Add(MyEnum.Three, this.divThree);

}

And before I get down-thumbs for not answering the OP's question...

Q: Now, my question is that is there any other way/solution to find the nested control in ASP.NET? A: Yes, avoid the need to search for them in the first place. Why search for things you already know are there? Better to build a system allowing reference of known objects.

Answer 5

The following example defines a Button1_Click event handler. When invoked, this handler uses the FindControl method to locate a control with an ID property of TextBox2 on the containing page. If the control is found, its parent is determined using the Parent property and the parent control's ID is written to the page. If TextBox2 is not found, "Control Not Found" is written to the page.

private void Button1_Click(object sender, EventArgs MyEventArgs)
{
      // Find control on page.
      Control myControl1 = FindControl("TextBox2");
      if(myControl1!=null)
      {
         // Get control's parent.
         Control myControl2 = myControl1.Parent;
         Response.Write("Parent of the text box is : " + myControl2.ID);
      }
      else
      {
         Response.Write("Control not found");
      }
}

Answer 6

Action Management On Controls

Create below class in base class. Class To get all controls:

public static class ControlExtensions
{
    public static IEnumerable<T> GetAllControlsOfType<T>(this Control parent) where T : Control
    {
        var result = new List<T>();
        foreach (Control control in parent.Controls)
        {
            if (control is T)
            {
                result.Add((T)control);
            }
            if (control.HasControls())
            {
                result.AddRange(control.GetAllControlsOfType<T>());
            }
        }
        return result;
    }
}

From Database: Get All Actions IDs (like divAction1,divAction2 ....) dynamic in DATASET (DTActions) allow on specific User.

In Aspx: in HTML Put Action(button,anchor etc) in div or span and give them id like

<div id="divAction1" visible="false" runat="server" clientidmode="Static">   
                <a id="anchorAction" runat="server">Submit
                        </a>                      
                 </div>

IN CS: Use this function on your page:

private void ShowHideActions()
    {

        var controls = Page.GetAllControlsOfType<HtmlGenericControl>();

        foreach (DataRow dr in DTActions.Rows)
        {          

            foreach (Control cont in controls)
            {

                if (cont.ClientID == "divAction" + dr["ActionID"].ToString())
                {
                    cont.Visible = true;
                }

            }
        }
    }