How to change the background color of unused space tab in C# winforms?

Question

Ex

  |Tab1|Tab2|Tab3| {    }
  |                     |
  |                     |
  |                     |
  |                     |
  |____________________         


        

Answer 1

Try adding the following code to your DrawItem event handler. Don't forget to set the DrawMode to "OwnerdrawFixed".

You might have to tweak it a bit to cover some margins which aren't painted.

private void tabControl1_DrawItem(object sender, System.Windows.Forms.DrawItemEventArgs e)
{
      SolidBrush fillbrush= new SolidBrush(Color.Red);


  //draw rectangle behind the tabs
  Rectangle lasttabrect = tabControl1.GetTabRect(tabControl1.TabPages.Count - 1);
  Rectangle background = new Rectangle();
  background.Location = new Point(lasttabrect.Right, 0);

  //pad the rectangle to cover the 1 pixel line between the top of the tabpage and the start of the tabs
  background.Size = new Size(tabControl1.Right - background.Left, lasttabrect.Height+1);
  e.Graphics.FillRectangle(fillBrush, background);
}

'This answer is much better than prior one. But the tabCtrl is not defined. It has to be tabControl1 control.

Answer 2

you can also create a custom tabcontrol as you did

public class mytab : TabControl
{
    public mytab()
        : base()
    {
        this.DrawMode = TabDrawMode.OwnerDrawFixed;
        this.DrawItem += new DrawItemEventHandler(tabControl1_DrawItem);
    }

    private void tabControl1_DrawItem(object sender, System.Windows.Forms.DrawItemEventArgs e)
    {
        Font fntTab;
        Brush bshBack;
        Brush bshFore;

        if (e.Index == this.SelectedIndex)
        {
            fntTab = new Font(e.Font, FontStyle.Bold);
            bshBack = new System.Drawing.Drawing2D.LinearGradientBrush(e.Bounds, SystemColors.Control, SystemColors.Control, System.Drawing.Drawing2D.LinearGradientMode.BackwardDiagonal);
            bshFore = Brushes.Black;
            //bshBack = new System.Drawing.Drawing2D.LinearGradientBrush(e.Bounds, Color.LightSkyBlue , Color.LightGreen, System.Drawing.Drawing2D.LinearGradientMode.BackwardDiagonal);
            //bshFore = Brushes.Blue;
        }
        else
        {
            fntTab = e.Font;
            bshBack = new SolidBrush(Color.Red);
            bshFore = new SolidBrush(Color.Aqua);

            //bshBack = new SolidBrush(Color.White);
            //bshFore = new SolidBrush(Color.Black);
        }

        string tabName = this.TabPages[e.Index].Text;
        StringFormat sftTab = new StringFormat();
        e.Graphics.FillRectangle(bshBack, e.Bounds);
        Rectangle recTab = e.Bounds;
        recTab = new Rectangle(recTab.X, recTab.Y + 4, recTab.Width, recTab.Height - 4);
        e.Graphics.DrawString(tabName, fntTab, bshFore, recTab, sftTab);


        Rectangle r = this.GetTabRect(this.TabPages.Count - 1);

        RectangleF tf =
            new RectangleF(r.X + r.Width,
            r.Y-5, this.Width - (r.X + r.Width)+5, r.Height+5);
        Brush b = Brushes.BlueViolet;

        e.Graphics.FillRectangle(b, tf);
    }

}

Answer 3

I think the only way to give that space a color is to override the OnPaintBackground method of the window, so just paste this on your form (window)

you must also change the Appearance Property to "Normal"

private void Form1_Load(object sender, EventArgs e)
{

}

protected override void OnPaintBackground(PaintEventArgs e)
{
    base.OnPaintBackground(e);
    Rectangle lasttabrect = tabControl1.GetTabRect(tabControl1.TabPages.Count - 1);
    RectangleF emptyspacerect = new RectangleF(
            lasttabrect.X + lasttabrect.Width + tabControl1.Left,
            tabControl1.Top + lasttabrect.Y, 
            tabControl1.Width - (lasttabrect.X + lasttabrect.Width), 
            lasttabrect.Height);

    Brush b = Brushes.BlueViolet; // the color you want
    e.Graphics.FillRectangle(b, emptyspacerect );
}

for me it's working perfectly