ColorDialog Class

ColorDialog Class

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Namespace

System.Windows.Forms

Createable

Yes

Description

Represents a common dialog box for selecting a color .

The ColorDialog object has properties for setting the initial appearance and functionality of the color dialog box, a property for returning the color selected by the user , and a method for showing the dialog box.

Selected ColorDialog Members

The following provides a brief description of the more important members of the ColorDialog class:

AllowFullOpen property

Returns or sets a Boolean value indicating whether the user can use the dialog box to define custom colors. The default is True .

AnyColor property

Returns or sets a Boolean value indicating whether the dialog box displays all available colors, although in Beta 2 of VB.NET, this property seems to have no effect. The default is False .

Color property

Returns an instance of a Color structure, which contains information about the color selected by the user. The Color structure, which is a type belonging to the System.Drawing namespace, has a number of members, including:

• Over 140 named color properties, from Red, Green, and Blue, to PapayaWhip, MistyRose, and MediumSeagreen. These properties return a Color structure.

• The Name property, which returns the name of the color, or its ARGB value for custom colors. (The A component is the alpha component of the color, which determines the color's opacity.)

• The R property, G property, and B property, which return a byte specifying the red, green, or blue color component of the RGB color value, respectively.

• The IsKnownColor, IsNamedColor, and IsSystemColor properties, which give information about the color.

CustomColors property

Represents an array of Integers used to set or return the set of custom colors that will be shown in the ColorDialog dialog box.

FullOpen property

Represents a Boolean property that sets or retrieves the value indicating whether the dialog box is opened with the controls used to create custom visible controls. (The default is False , but the user can always click the Custom Colors button to display the custom colors controls.)

Reset method

Resets the dialog box by setting all options and custom colors to their default values and setting the selected color to black.

SolidColorOnly property

For systems displaying 256 colors or less, if this property is set to True , restricts the dialog box to solid colors only, that is, to colors that are not composites of other colors.

VB.NET/VB 6 Differences

While the ColorDialog class is implemented in the .NET Base Class Library, VB 6 offered the CommonDialog custom control. Although the two offer similar functionality, their public interfaces are almost completely different.

Example

The following code asks the user for a color and displays that color:

 Dim cd As New ColorDialog(  ) Dim c As New Color(  ) If cd.ShowDialog(  ) = DialogResult.OK Then     Console.WriteLine(cd.Color.ToString)     Console.WriteLine(cd.Color.Name) Else     Console.WriteLine("No color chosen") End If 

Note the use of the DialogResult enumeration to check user action on the dialog box. Here is the precise output if red is selected:

 Color [Alpha=255, Red=255, Green=0, Blue=0] ffff0000