Aynchronous Color Fading

• Download source code - 2.66 KB
• Download sample project - 28.2 KB

Introduction

This is a simple class with a shared method for asynchronously fading a color property from one color to another. I needed a way to indicate to users that they had saved or deleted something, so I wanted a way to slowly fade the background color of a textbox.

Code Usage

There are three overloads of the shared method. The basic method takes seven parameters:

• container - The object that contains the color property to be fading. For example, a text box or label.
• colorProperty - The name of the color property to change - this has to be a string, for example, "ForeColor" or "BackColor".
• startColor - The color that will begin the fade.
• endColor - The color that will end the the fade.
• steps - The number of steps to take in fading from the start color to the end color.
• delay - A delay in milliseconds between each step in the fade.
• callback - An optional function that will be called when the fade completes.

The second overload takes an intermediate color and the number of steps for fading, and the final overload takes a list of colors and steps.

Problem

I wanted to simply pass the color property itself, and pass it byRef so that I could change it, but I couldn't figure out how to do it. I don't know if you can pass a byRef parameter to another thread. Anyway, that's why the method requires a container object and the name of the property to change.

Examples

Dim textBox1 As New TextBox() 
Visual.FadeColor(textBox1, "BackColor", Color.Green, Color.White, _
                 25, 25, AddressOf DoneFading)

Private Sub DoneFading(ByVal container As Object, ByVal colorProperty As String)
    MsgBox("Done fading!")
End Sub

Conclusion

Overall, it's pretty simple, but hopefully useful. If you have any suggestions, feel free to let me know.