Prevent duplicate MDI children forms

c# mdi children
user picture user · Oct 12, 2009 · Viewed 21.8k times · Source

Is there a way to prevent the opening of a certain form within an MDI container if that said form is already opened?

Answer

Fredrik Mörk picture Fredrik Mörk · Oct 12, 2009

You can interate over the OpenForms collection to check if there is already a form of the given type:

foreach (Form form in Application.OpenForms)
{
    if (form.GetType() == typeof(MyFormType))
    {
        form.Activate();
        return;
    }
}

Form newForm = new MyFormType();
newForm.MdiParent = this;
newForm.Show();

Related questions

How to make WinForms UserControl fill the size of its container

I am trying to create a multilayout main screen application. I have some buttons at the top that link to the main section of the application (e.g. management window for each entity in the Model) Clicking any of these …

Read More
Maximize MDI child form

I'm working on a legacy WinForms MDI application and have some trouble making the child forms behave as I want. My objective is to have the child form always maximized (docked). The problem is, that even if I set MaximizeBox …

Read More
C# Panel As MDI Container

In C# i want to create a panel that has the properties of a MDI container ie. isMdiContainer = true. I tried something like this form.MDIParent = this.panel1; But that dont work. Any suggestions?

Read More