Windows Forms: wait until another form closes

Question

I have a situation in which formA needs to update some data, but only after formB has closed. Is there a simple way to do this?

private void newProjectButton_Click(object sender, EventArgs e)
{
    NewProjectForm newProjectForm = new NewProjectForm();
    newProjectForm.Show();

    //wait for newProjectForm to close...

    DataTable dt = Util.ToDataTable(ProjectParticipantTable.GetUserProjectsDetails(Util.currentUserId));
    userProjectsDGV.DataSource = dt;
}

I'm guessing `formB` isn't modal? Seems to be too obvious a solution. — Setsu, Feb 02 '17 at 00:11
As Reza suggest change the `Show()` to `ShowDialog();` You will not be able to do anything with your other currently open forms until `newProjectForm` is closed. — JohnG, Feb 02 '17 at 00:14

NicoRiff · Answer 1 · 2017-02-02T00:27:26.847

3

You have to make use of ShowDialog() method, and managhe the DialogResult property. For doing that, you have to set the DialogResult set on some part of NewProjectForm, that can be done setting the property in a button, or simply setting it by code. That will fire the DialogResult to your parent form and close the Form

You can do that this way:

using(NewProjectForm newProjectForm = new NewProjectForm())
{
   if(newProjectForm.ShowDialog() == DialogResult.OK)
   {
       DataTable dt = Util.ToDataTable(ProjectParticipantTable.GetUserProjectsDetails(Util.currentUserId));
       userProjectsDGV.DataSource = dt;
   }
}

edited Feb 02 '17 at 00:27

answered Feb 02 '17 at 00:18

NicoRiff

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[Do I need to Dispose a Form after the Form got Closed?](http://stackoverflow.com/a/39501121/3110834) – Reza Aghaei Feb 02 '17 at 00:25
@RezaAghaei you ´ve got it. I updated my answer for keeping up with good practices – NicoRiff Feb 02 '17 at 00:28

tcwicks · Answer 2 · 2017-02-02T23:54:26.457

If you don't want to use the modal showdialog mode you can also use this approach.

private void newProjectButton_Click(object sender, EventArgs e)
{
    NewProjectForm newProjectForm = new NewProjectForm();
    newProjectForm.FormClosed += NewProjectForm_FormClosed;
    newProjectForm.Show();
}

private void NewProjectForm_FormClosed(object sender, System.Windows.Forms.FormClosedEventArgs e)
{
    ////will run when new form is closed

    DataTable dt = Util.ToDataTable(ProjectParticipantTable.GetUserProjectsDetails(Util.currentUserId));
    userProjectsDGV.DataSource = dt;
}

If you want only a singleton then make the newProjectForm variable a static singleton.

Windows Forms: wait until another form closes

2 Answers2