Calling the Control.ResumeLayout method forces an immediate layout if there are any pending layout requests. When the performLayout parameter is set to true, an immediate layout occurs if there are any pending layout requests.
The Control.SuspendLayout and Control.ResumeLayout methods are used in tandem to suppress multiple Control.Layout events while you adjust multiple attributes of the control. For example, you would typically call the Control.SuspendLayout method, then set the Control.Size, Control.Location, Control.Anchor, or Control.Dock properties of the control, and then call the Control.ResumeLayout method to enable the changes to take effect.
There must be no pending calls to Control.SuspendLayout for Control.ResumeLayout to be successfully called.
When adding several controls to a parent control, it is recommended that you call the Control.SuspendLayout method before initializing the controls to be added. After adding the controls to the parent control, call the Control.ResumeLayout method. This will increase the performance of applications with many controls.