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Change other form text on event close

I want to change the label text in my MdiParent Form when the child form is closed. but I am getting this error "An unhandled exception of type 'System.NullReferenceException' occurred in yourprogram.exe". This is my code:

        private void Employees_FormClosing(object sender, FormClosingEventArgs e)
    {
        (MdiParent as MainForm).setStatusText = "Ready";
    }

I have this code in my MdiParent Form:

public string setStatusText
    {
        set
        {
            tsStatus.Text = value;
        }
    }

I tried it too on Employees_FormClosed Event, but I still get the same error. I just couldn't figure out why this is giving me a null reference when I instantiated the class.

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1 answer


This code is taken from your comment:

private void addEmployeeToolStripMenuItem_Click(object sender, EventArgs e)
{
    Employees emp = new Employees();
    emp.MdiParent = this.MdiParent;
    emp.Show();
    tsStatus.Text = "Adding Employee";
}

When I understand this correctly, your method setStatusText

is in the same class as the method addEmployeeToolStripMenuItem_Click

. This means the line emp.MdiParent = this.MdiParent;

is wrong. This must be emp.MdiParent = this;

because you do not want to establish a parent for your child, you want to establish yourself as the parent of your child.



EDIT:

When you get NullReferenceException

using it as

, it can mean two things. Either your variable, in this case MdiParent

, is equal null

, or your variable is not of the correct type, in this case MainForm

.

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