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How can MDI parent access controls on the active MDI child form?

I have a basic MDI application that does text editing in addition to some data processing. I'm trying to accesscontrols on the active MDI child form from the parent. For instance, when the "Save" menu option is clicked from the parent's menu bar, I'd like to save the text in the active MDI child form's ListBox.

I need C# examples for this, please. Thank you very much in advance!!!

annulik Wednesday, August 13, 2008 6:07 PM

If all the MDI child forms are of the same type - then you can just expose the ListBox on the child form by either changing it's modifier or adding a property with a getter that will return the ListBox. Then, on the "Save" menu just cast the this.ActiveMdiChild to your form's type and use the property to get the ListBox.

If you have multiple types of MdiChild forms, you can either have all of them to inherit from one base form (with the ListBox and a property getter on it) or better off, just implement an interface with a ListBox property.

Code Snippet

// declare the interface
public interface IListBoxOwner
{
ListBox ListBox
{
get;
}
}

// form2 is one of the possible MdiChild forms
public partial class Form2 : Form, IListBoxOwner
{
public Form2()
{
InitializeComponent();
}

#region IListBoxOwner Members

public ListBox ListBox
{
get { return this.listBox1; }
}

#endregion
}

// in the MdiContainer form, the Save menu
private void saveToolStripMenuItem_Click(object sender, EventArgs e)
{

if (this.ActiveMdiChild is IListBoxOwner)

{

(this.ActiveMdiChild as IListBoxOwner).ListBox.Items.Add("asdasd");

}

hth,
Lior.

Lior Salem Wednesday, August 13, 2008 10:03 PM

Code Snippet