How to avoid opening multiple instance of a form in C# windows forms application?

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Hello,

I have write a program which has an About button, pressing the about button on the main form will open another form which gives some information about the program, however, clicking the about button will make another instances of such form, how can I avoid it?

my code is:

C#

private void aboutToolStripMenuItem1_Click(object sender, EventArgs e)
{
    FormAbout formAbout = new FormAbout();
    formAbout.Show();
}

Thanks in advance
AM

Posted 11-Mar-15 4:45am

ARMS_DEIR

Updated 11-Mar-15 4:46am

v2

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2 solutions

Solution 2

I think OriginalGriff has given you a correct, solid, answer here;.

A factor in how you manage a "secondary" Form like this is the extent to which you need to do possibly "expensive" (time, memory) work to fill that secondary Form with its relevant content before you show it.

Why not create the Form once, populate its fields that do not change once, and then re-use the Form ... rather than creating a new instance of the secondary Form each time you want to show it ?

Posted 11-Mar-15 6:19am

BillWoodruff

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OriginalGriff · Accepted Answer · 2015-03-11T04:48:00

Solution 1

Simplest way is to use ShowDialog instead:

C#

private void aboutToolStripMenuItem1_Click(object sender, EventArgs e)
{
    FormAbout formAbout = new FormAbout();
    formAbout.ShowDialog();
}

Posted 11-Mar-15 4:48am

OriginalGriff