This is a short article on how to use the
ComboBox control as a color picker to display and select colors. A small strip of the color and its name for all the known colors is shown in the drop down of the
ComboBox control as shown below:
ComboBox control has a
DrawItem event which needs to be implemented in the code to achieve this. There is a property called
DrawMode for the
ComboBox control which determines whether the Operating System or the code will handle the drawing of the items in the list. This property must be set to ‘
OwnerDrawFixed’ using the Properties window in order for the
DrawItem event implementation to be called.
Using the code
The solution contains only a single project, and that project contains a single form. On the form, I have a button, the click of which will populate the combo box with all the named colors in the
Color struct. I am using the selected color for changing the background color of a panel on the form.
The button click implementation is as shown below. I have used Reflection to get a collection of all the colors in the
System.Drawing.Color structure. The color names are then added to the combo box.
private void btnLoad_Click(object sender, EventArgs e)
ArrayList ColorList = new ArrayList();
Type colorType = typeof(System.Drawing.Color);
PropertyInfo propInfoList = colorType.GetProperties(BindingFlags.Static |
BindingFlags.DeclaredOnly | BindingFlags.Public);
foreach (PropertyInfo c in propInfoList)
DrawItem event, the
Graphics object (which can be obtained through the
Graphics property of the
DrawItemEventArgs) is used to draw a strip of the named color using its
FillRectangle method. The
DrawString method is used to add the name of the color. The
DrawItem event will be triggered for each item added to the combo box.
private void cmbboxClr_DrawItem(object sender, DrawItemEventArgs e)
Graphics g = e.Graphics;
Rectangle rect = e.Bounds;
if (e.Index >= 0)
string n = ((ComboBox)sender).Items[e.Index].ToString();
Font f = new Font("Arial", 9, FontStyle.Regular);
Color c = Color.FromName(n);
Brush b = new SolidBrush(c);
g.DrawString(n, f, Brushes.Black, rect.X, rect.Top);
g.FillRectangle(b, rect.X + 110, rect.Y + 5,
rect.Width -10, rect.Height - 10);
A snapshot of the sample form:
You can download the full project and open it in Visual Studio 2005 for more details.