C#

BillWoodruff wrote:

But, I am surprised that this code did not run into the issue of a collection
which is self-modified during a foreach, or for, loop, throwing a compile
error.

//
private MdiClient theMDIClientControl;
//
// note: don't need to recurse
Control[] potentialMDIClientControls = this.Controls.Find("MdiClient", false);
//
if (potentialMDIClientControls.Length > 0) theMDIClientControl = potentialMDIClientControls[0] as MdiClient;

private void Form1_Load(object sender, EventArgs e)
{
    MdiClient ctlMDI;
    //' Loop through all of the form's controls looking
    //' for the control of type MdiClient.
    foreach (Control ctl in this.Controls)
    {
        try
        {
            // Attempt to cast the control to type MdiClient.
            ctlMDI = (MdiClient)ctl;

            // Set the BackColor of the MdiClient control.
            ctlMDI.BackColor = Color.White;
        }
        catch (InvalidCastException exc)
        {
            // Catch and ignore the error if casting failed.
        }
    }
}

Alisaunder wrote:

try
{
// Attempt to cast the control to type MdiClient.
ctlMDI = (MdiClient)ctl;

private void MdiClientExample()
{
    foreach (Control c in this.Controls)
    {
        if (c is MdiClient)
        {
            MdiClient mc = (MdiClient)c;
            ...
        }
    }
}