C# Windows Forms glitch while creating a control

user_13946902 0
Viewed 280

I somehow noticed, that while I'm creating a control in my application, it first appears as weird rectangle and then it "shrinks" to it's correct form.

First thing you'll see after creation

Correctly created object

My question is, why I first see the rectangle in top left corner and then it suddenly changes to it's correct form. It's like split second thing (I had to use Thread.Sleep 'cos it's impossible to screenshot it), but my eyes can still see this and I'm really triggered when it's happening.

This is the code, where I'm creating the control:

var label = new Label
{
    AutoSize = true,
    TextAlign = ContentAlignment.MiddleLeft,
    Font = new Font("Courier New", 9F, FontStyle.Regular,
        GraphicsUnit.Point, 238),
    Text = keyword,
    Margin = new Padding(0, 6, 25, 3),
    Padding = new Padding(0, 3, 0, 0)
};

var button = new Button
{
    BackgroundImage = Image.FromFile("../../../Images/cross_200x200.png"),
    BackgroundImageLayout = ImageLayout.Stretch,
    Dock = DockStyle.Right,
    Width = 21,
    Height = 21,
    FlatStyle = FlatStyle.Flat,
};
button.FlatAppearance.BorderSize = 0;

var pan = new Panel
{
    AutoSize = true,
    Padding = new Padding(0, 0, 1, 1),
    BackColor = Color.PowderBlue,
    BorderStyle = BorderStyle.FixedSingle,
    Tag = keyword
};

button.Click += delegate
{
    _keywords.Remove(pan.Controls.OfType<Label>().First().Text);
    pan.Dispose();
    StatusLabel.Text = $@"Removed {keyword}";
};

pan.Controls.Add(label);
pan.Controls.Add(button);

FlowLayoutPanelMain.Controls.Add(pan);

Everytime a "keyword" is added to FlowLayoutPanel control, at first it's a rectangle in top left corner and immediately after that it's fine.

forms controls windows c#
2 Answers

With help from a friend of mine, we figured out, that this is happening due to Windows Forms old technology (It's probably not happening in .NET Core's WPF) and it's inability of creating controls at runtime. So, the offered solution for this seems to be just .Hide() the control, .Add() it to the FlowLayoutPanel and then simply .Show() it back, now my eyes will be satisfied.

...

pan.Hide();
FlowLayoutPanelMain.Controls.Add(pan);
pan.Show();

...
user_139469020

Try to remove AutoSize property and assign a new Size() to the panel

AutoSize = false,

Worked for me

user_177962130
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