Select all combo boxes on winform by LINQ [duplicate] - winforms

Question

I have multiple pictureboxes and I need to load random images into them during runtime. So I thought it would be nice to have a collection of all pictureboxes and then assign images to them using a simple loop. But how should I do it? Or maybe are there any other better solutions to such problem?

Answer 1

Using a bit of LINQ:
foreach(var pb in this.Controls.OfType<PictureBox>())
{
//do stuff
}
However, this will only take care of PictureBoxes in the main container.

Answer 2

You could use this method:
public static IEnumerable<T> GetControlsOfType<T>(Control root)
where T : Control
{
var t = root as T;
if (t != null)
yield return t;
var container = root as ContainerControl;
if (container != null)
foreach (Control c in container.Controls)
foreach (var i in GetControlsOfType<T>(c))
yield return i;
}
Then you could do something like this:
foreach (var pictureBox in GetControlsOfType<PictureBox>(theForm)) {
// ...
}

Answer 3

If you're at least on .NET 3.5 then you have LINQ, which means that since ControlCollection implements IEnumerable you can just do:
var pictureBoxes = Controls.OfType<PictureBox>();

Answer 4

I use this generic recursive method:
The assumption of this method is that if the control is T than the method does not look in its children. If you need also to look to its children you can easily change it accordingly.
public static IList<T> GetAllControlsRecusrvive<T>(Control control) where T :Control
{
var rtn = new List<T>();
foreach (Control item in control.Controls)
{
var ctr = item as T;
if (ctr!=null)
{
rtn.Add(ctr);
}
else
{
rtn.AddRange(GetAllControlsRecusrvive<T>(item));
}
}
return rtn;
}

Answer 5

A simple function, easy to understand, recursive, and it works calling it inside any form control:
private void findControlsOfType(Type type, Control.ControlCollection formControls, ref List<Control> controls)
{
foreach (Control control in formControls)
{
if (control.GetType() == type)
controls.Add(control);
if (control.Controls.Count > 0)
findControlsOfType(type, control.Controls, ref controls);
}
}
You can call it on multiple ways.
To get the Buttons:
List<Control> buttons = new List<Control>();
findControlsOfType(typeof(Button), this.Controls, ref buttons);
To get the Panels:
List<Control> panels = new List<Control>();
findControlsOfType(typeof(Panel), this.Controls, ref panels);
etc.

Answer 6

Here's another version since the existing provided ones weren't quite what I had in mind. This one works as an extension method, optionally, and it excludes checking the root/parent container's type. This method is basically a "Get all descendent controls of type T" method:
public static System.Collections.Generic.IEnumerable<T> ControlsOfType<T>(this System.Web.UI.Control control) where T: System.Web.UI.Control{
foreach(System.Web.UI.Control childControl in control.Controls){
if(childControl is T) yield return (T)childControl;
foreach(var furtherDescendantControl in childControl.ControlsOfType<T>()) yield return furtherDescendantControl;
}
}

Answer 7

public static List<T> FindControlByType<T>(Control mainControl,bool getAllChild = false) where T :Control
{
List<T> lt = new List<T>();
for (int i = 0; i < mainControl.Controls.Count; i++)
{
if (mainControl.Controls[i] is T) lt.Add((T)mainControl.Controls[i]);
if (getAllChild) lt.AddRange(FindControlByType<T>(mainControl.Controls[i], getAllChild));
}
return lt;
}

Answer 8

This to me is by far the easiest. In my application, I was trying to clear all the textboxes in a panel:
foreach (Control c in panel.Controls)
{
if (c.GetType().Name == "TextBox")
{
c.Text = "";
}
}

Answer 9

Takes Control as container into account:
private static IEnumerable<T> GetControlsOfType<T>(this Control root)
where T : Control
{
if (root is T t)
yield return t;
if (root is ContainerControl || root is Control)
{
var container = root as Control;
foreach (Control c in container.Controls)
foreach (var i in GetControlsOfType<T>(c))
yield return i;
}
}