how to change transparency of a color in c#

Question

I am using SSRS reportviewer to generate a report using objects. In my program, I am asking the user to input a string of commonly known colors such as \"Red\", \"<

Answer 1

You can set with this function

    static Color SetTransparency(int A, Color color)
    {
        return Color.FromArgb(A, color.R, color.G, color.B);
    }

Answer 2

I created a handy extension method.

public static class ColorExtensions
{
    ...
    public static Color WithA(this Color color, int newA) => Color.FromArgb(newA,color);
}

Usage:

newitem.ChartColor = "red";
Color mycolor = Color.FromName(newitem.ChartColor);

Color myColorAlt1 = myColor.WithA(0x56);
Color myColorAlt2 = myColor.WithA(0x28);

or, if you needed it right away:

Color mycolor = Color.FromName(newitem.ChartColor).WithA(0x56);

Answer 3

There is a method that does exactly what you need Color.FromArgb(int alpha, Color baseColor).

Valid alpha values are 0 through 255. Where 255 is the most opaque color and 0 a totally transparent color.

Use example

Color newColor = Color.FromArgb(newAlpha, mycolor);

Answer 4

I think what needs to be included among these answers is that the alpha value indicates how transparent the color is with 0 being the most transparent and with 255 being the most opaque. Here is a summary:

                     A L P H A    V A L U E
0 [<--- most transparent]  ... ... ... [most opaque --->] 255