How to make OnPaint run different ControlPaint.DrawBorderStyle functions, when user selects the control

Question

I have a UserControl (Groupbox) with the following onPaint method:

protected override void OnPaint(PaintEventArgs e) {
    Size tSize = TextRenderer.MeasureText(this.Text, this.Font);
    Rectangle borderRect = e.ClipRectangle;
    borderRect.Y += tSize.Height / 2;
    borderRect.Height -= tSize.Height / 2;
    ControlPaint.DrawBorder(e.Graphics, borderRect, this.borderColor, ButtonBorderStyle.Solid);

    Rectangle textRect = e.ClipRectangle;
    textRect.X += 6;
    textRect.Width = tSize.Width;
    textRect.Height = tSize.Height;
    e.Graphics.FillRectangle(new SolidBrush(this.BackColor), textRect);
    e.Graphics.DrawString(this.Text, this.Font, new SolidBrush(this.ForeColor), textRect);
}

When the user selects this control, I want to change the border to be darker, so I tried the following logic:

protected override void OnPaint(PaintEventArgs e) {
    Size tSize = TextRenderer.MeasureText(this.Text, this.Font);
    Rectangle borderRect = e.ClipRectangle;
    borderRect.Y += tSize.Height / 2;
    borderRect.Height -= tSize.Height / 2;
    if (ContainsFocus) {
        ControlPaint.DrawBorder(e.Graphics, borderRect,
            this.borderColor, 4, ButtonBorderStyle.Solid,
            this.borderColor, 4, ButtonBorderStyle.Solid,
            this.borderColor, 4, ButtonBorderStyle.Solid,
            this.borderColor, 4, ButtonBorderStyle.Solid);
    } else {
        ControlPaint.DrawBorder(e.Graphics, borderRect, this.borderColor, ButtonBorderStyle.Solid);
    }

    Rectangle textRect = e.ClipRectangle;
    textRect.X += 6;
    textRect.Width = tSize.Width;
    textRect.Height = tSize.Height;
    e.Graphics.FillRectangle(new SolidBrush(this.BackColor), textRect);
    e.Graphics.DrawString(this.Text, this.Font, new SolidBrush(this.ForeColor), textRect);
}

My control seems to be continuously entering else even when I select my user control. Any help in this direction will be appreciated.

You need to override OnEnter() and OnLeave() and call this.Invalidate(). That gets the control to repaint itself when it gains and loses focus. Easy peasy. — Hans Passant, Dec 10 '16 at 13:58
Hi @HansPassant, I am not sure how to do this. Could you please help me out. I am not able to get the e.Graphics to work inside onEnter or onLeave... — Ganesh Kamath - 'Code Frenzy', Dec 10 '16 at 14:22
I said "call this.Invalidate()", that does not sound much like "get the e.Graphics to work" does it? Sample code [is here](http://stackoverflow.com/a/3562449/17034). — Hans Passant, Dec 10 '16 at 14:26
@HansPassant, this.Invalidate is not changing the borderthickeness for selection change event of group box. I might have got something wrong, could you please post an answer that i could try? — Ganesh Kamath - 'Code Frenzy', Dec 10 '16 at 18:27

Ganesh Kamath - 'Code Frenzy' · Accepted Answer · 2016-12-12T06:14:30.203

To solve this problem I used the onMouseClick event with a combination of declaring a constructor which set the initial borderColor to a different value. like so

    private Color borderColor;
    private int entered;

    public TUserControlGroupBox() {
        this.borderColor = SystemColors.ControlDark;
    }

    public Color BorderColor {
        get { return this.borderColor; }
        set { this.borderColor = value; }
    }

    public BorderState Border {
        set {
            switch (value) {
                case BorderState.Unselected:
                    this.BorderColor = Color.LightGray;
                    break;
                case BorderState.Selected:
                    this.BorderColor = Color.Black;
                    break;
                case BorderState.SelectedFirst:
                    this.BorderColor = SystemColors.ControlDark;
                    break;
            }

            this.Invalidate();
        }
    }

    protected override void OnPaint(PaintEventArgs e) {
        Size tSize = TextRenderer.MeasureText(this.Text, this.Font);
        Rectangle borderRect = e.ClipRectangle;
        borderRect.Y += tSize.Height / 2;
        borderRect.Height -= tSize.Height / 2;
        if ((this.BorderColor == Color.Black || this.borderColor == SystemColors.ControlDark) && this.entered == 1) {
            ControlPaint.DrawBorder(e.Graphics, borderRect,
                this.borderColor, 4, ButtonBorderStyle.Solid,
                this.borderColor, 4, ButtonBorderStyle.Solid,
                this.borderColor, 4, ButtonBorderStyle.Solid,
                this.borderColor, 4, ButtonBorderStyle.Solid);
        } else {
            ControlPaint.DrawBorder(e.Graphics, borderRect, this.borderColor, ButtonBorderStyle.Solid);
        }
        Rectangle textRect = e.ClipRectangle;
        textRect.X += 6;
        textRect.Width = tSize.Width;
        textRect.Height = tSize.Height;
        e.Graphics.FillRectangle(new SolidBrush(this.BackColor), textRect);
        e.Graphics.DrawString(this.Text, this.Font, new SolidBrush(this.ForeColor), textRect);
    }

    protected override void OnMouseClick(MouseEventArgs e) {
        this.entered = 1;
        this.Invalidate();
        base.OnMouseClick(e);
    }

Hope this answer helps those looking for a similar solution in the future.

How to make OnPaint run different ControlPaint.DrawBorderStyle functions, when user selects the control

1 Answers1