CODEWITHSUNDEEP
c#winforms
libjup
libjup

Reputation: 4089

Simple panel-slider in C#

I'm currently developing a C# application. Right now I'm trying to realize a simple slider: 

|--------------------------|
|                          |
|  |--------------------|  |
|  |                    |  |
|  |       Panel1       |  |
|  |       Panel2       |  |
|  |                    |  |
|  |--------------------|  |
|           x x x          |
|--------------------------|

I have two panels with exactly the same size. Panel1 is just needed for displaying a border and setting the boundaries for panel2 which is then dynamically exchanged.

If the second x is clicked, panel2 should move to the left and panel3 should come from the right and also move to the left.

Basically I have the following code:

Panel panel2 = panelArray[0];
Panel panel3 = panelArray[1];

The following code should now perform the slide:

for (int i = 0; i <= 100; i++)
{
    panel2.Location = new Point(panel2.Location.X - i, panel2.Location.Y);
    System.Threading.Thread.Sleep(10);
}

for (int i = 0; i <= 100; i++)
{
    panel3.Location = new Point(100 - i, panel3.Location.Y);
    System.Threading.Thread.Sleep(10);
}

Somehow the first panel is slided-out perfectly but panel2 is not sliding. It's just displayed after the loop is executed.

Any idea why panel2 isn't performing the slide? I'm using WinForms.

Upvotes: 0

Views: 3018

Answers (2)

Lucero
Lucero

Reputation: 60236

The problem is that you're not allowing the message pump to run by forcing a sleep. The suggested Application.DoEvents triggers the message pump, but it isn't a good solution because your code still blocks most of the time and you may even run in infinite loops with this pattern (e.g. if DoEvents re-enters the event you're calling it from).

Instead of using Thread.Sleep you should rather use a (Winforms) Timer. This will solve the UI update problem and also keep the UI alive while the slider moves.

Upvotes: 0

John
John

Reputation: 2792

Try adding Application.DoEvents in the body of your loop after the location change. The UI needs a chance to catch up.

Upvotes: 1

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