How do I prevent a form object from disposing on c

问题:

I am using an MDIParent Form. When I close its child, the object of the child disposes. Is there a way to set child visibility to false instead of disposing?

回答1:

By default, when you close a form, it will be disposed. You have to override the Closing event to prevent it, for example:

// Use this event handler for the FormClosing event.
private void MyForm_FormClosing(object sender, FormClosingEventArgs e)
{
  this.Hide();
  e.Cancel = true; // this cancels the close event.
}

回答2:

Yes. You can call the form's "Hide" method.

You can also override OnClosed and not call its base implementation; HOWEVER, when you DO want to dispose of the form, this may get in your way.

回答3:

You can cancel the close event and hide instead.

private void Form1_FormClosing(object sender, FormClosingEventArgs e)
    {
        e.Cancel = true;
        this.Hide();
    }

回答4:

Sure, you can cancel the close and hide it. It doesn't seem like a good thing to do, but you definitely can.

See Form.FormClosing Event (MSDN).

回答5:

    void SaveInfo()
{
blnCanCloseForm = false;
Vosol[] vs = getAdd2DBVosol();
if (DGError.RowCount > 0)
return;

Thread myThread = new Thread(() =>
{
this.Invoke((MethodInvoker)delegate {
    picLoad.Visible = true;
    lblProcces.Text = "Saving ...";
});
int intError = setAdd2DBVsosol(vs);
Action action = (() =>
{
    if (intError > 0)
    {
        objVosolError = objVosolError.Where(c => c != null).ToArray();
        DGError.DataSource = objVosolError;// dtErrorDup.DefaultView;
        DGError.Refresh();
        DGError.Show();
        lblMSG.Text = "Check Errors...";
    }
    else
    {
        MessageBox.Show("Saved All Records...");
        blnCanCloseForm = true;
        this.DialogResult = DialogResult.OK;
        this.Close();
    }

});
this.Invoke((MethodInvoker)delegate {
    picLoad.Visible = false;
    lblProcces.Text = "";
});
this.BeginInvoke(action);
});
myThread.Start();
}

void frmExcellImportInfo_FormClosing(object s, FormClosingEventArgs e)
{
    if (!blnCanCloseForm)
        e.Cancel = true;
}