Your question isn't as clear as it could be. I am interpreting it as "how can I get the color that was selected on the dialog box
passed to the main form where I want to use that color"
@NotPoliticallyCorrect has given you a good link if it is only color you are interested in...
ColorDialog Class (System.Windows.Forms)[
^]
If you want to pass more general information from a Dialog to a form have a look at this Tip -
Transferring information between two forms, Part 2: Child to Parent[
^] - it's a simpler to read version of what is going on in Solution 1.