use Multiple forms in one Csharp panel in one Windows Form panel
subForm = new SubFormYouWantToLoad();
subForm.TopLevel = false;
subForm.FormBorderStyle = FormBorderStyle.None;
ContainerPanel.Controls.Add(subForm , 0, 1);
subForm .Visible = true;
// You can add this code when you click on the specific button.
// Here each subform is added to the Panel as a Control.
// You should remove the subform from the panel's control list before
// adding another subform. For this ,it is better to remove,close and
// dispose the first one.
ContainerPanel.Controls.Remove(activeform);
activeform.Close();
activeform.Dispose();