FloodFill

C# Signature:

[DllImport("gdi32.dll")]
static extern bool FloodFill(IntPtr hdc, int nXStart, int nYStart,
   uint crFill);

VB Signature

Declare Function FloodFill Lib "gdi32" (ByVal hDC As Integer, ByVal x As Integer, ByVal y As Integer, ByVal crColor As Integer) As Integer