DropDown, Theme/Color Changer

Question

Okay... First of all how do I make my ComboBox have a Dropdown, or my TextBox? To add these choices Choose Theme... -Default -Green -Red -Blue -Black -Silver/White Secondly, I am trying to use this code to change them... But there are errors... Here is the code. private void textBoxDropDown1_TextChanged(object sender, EventArgs e) { switch (textBoxDropDown1.SelectedText) { case "default": { ChangeTheme(menuStrip1, Image.FromFile("http://moddersworld.com/images/test5.png"), ImageLayout.Stretch, Color.White); ChangeTheme(BackgroundImage, Image.FromFile("http://moddersworld.com/images/bgom.png"), ImageLayout.Stretch, Color.White); } break; case "green": { ChangeTheme(menuStrip1, Image.FromFile("http://moddersworld.com/images/test4.png"), ImageLayout.Stretch, Color.LimeGreen); ChangeTheme(BackgroundImage, Image.FromFile("http://moddersworld.com/images/grn1.png"), ImageLayout.Stretch, Color.White); } break; case "red": { ChangeTheme(menuStrip1, Image.FromFile("http://moddersworld.com/images/test9.png"), ImageLayout.Stretch, Color.White); ChangeTheme(BackgroundImage, Image.FromFile("http://moddersworld.com/images/red7.png"), ImageLayout.Stretch, Color.White); } break; case "blue": { ChangeTheme(menuStrip1, Image.FromFile("http://moddersworld.com/images/test0.png"), ImageLayout.Stretch, Color.White); ChangeTheme(BackgroundImage, Image.FromFile("http://moddersworld.com/images/blue0.png"), ImageLayout.Stretch, Color.White); } break; case "silver/white": { ChangeTheme(menuStrip1, Image.FromFile("http://moddersworld.com/images/test7.png"), ImageLayout.Stretch, Color.Black); ChangeTheme(BackgroundImage, Image.FromFile("http://moddersworld.com/images/whitesliver.png"), ImageLayout.Stretch, Color.Black); } break; case "black": { ChangeTheme(menuStrip1, Image.FromFile("http://moddersworld.com/images/test4.png"), ImageLayout.Stretch, Color.White); ChangeTheme(BackgroundImage, Image.FromFile("http://moddersworld.com/images/black.png"), ImageLayout.Stretch, Color.White); } break;