Question

I have the following code:

namespace FVProductions.Base
{
    public struct Color
    {
        public byte B, G, R, A;

        public Color(float r, float g, float b, float a)
        {
            R = (byte)(Math.Min(1.0f, Math.Max(0.0f, r)) * 255);
            G = (byte)(Math.Min(1.0f, Math.Max(0.0f, g)) * 255);
            B = (byte)(Math.Min(1.0f, Math.Max(0.0f, b)) * 255);
            A = (byte)(Math.Min(1.0f, Math.Max(0.0f, a)) * 255);
        }

        public Color(Vector3 rgb)
            :this(rgb.X,rgb.Y,rgb.Z,1)
        {
        }
    }
}

namespace FVProductions.Base.Graphics
{
    public class ShaderParameter<T>
    {
        private T Value;
        public T GetValue() { return Value; }
    }
}

namespace FVProductions.NewGame
{
    public class TerrainShader : Shader, IFullTextured, IStandardLit
    {
        private ShaderParameter<Vector3> epAmbient;

        public FVProductions.Base.Color AmbientColor
        {
            get { return new FVProductions.Base.Color(epAmbient.GetValue()); }
            set { epAmbient.SetValue(value.ToVector3()); }
        }
    }
}

The type, FVProductions.Base.Color is in a referenced library. epAmbient.GetValue returns a Vector3 and FVProductions.Base.Color has a constructor with a single Vector3 parameter. The project does not reference System.Drawing. However, the compiler is generating the following error:

error CS0012: The type ‘System.Drawing.Color’ is defined in an assembly that is not referenced. You must add a reference to assembly ‘System.Drawing, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a’.

That’s on the TerrainShader.AmbientColor get{} line, at the return keyword. Why would the compiler ever assume an explicitly declared type is another?

Answer 1

Found it. FVProductions.Base.Color is a base class in a base library and has a constructor that accepts a System.Drawing.Color. The project that has the problem code does not reference System.Drawing. When using the Color class, it was having trouble linking the System.Drawing.Color constructor even though it wasn’t used. So, I discovered two solutions:

Have the upper library reference the System.Drawing library even though it won’t be used.

Remove the System.Drawing.Color constructor from FVProductions.Base.Color.

Either will allow the project to compile.