Introduction
In GDI+, for drawing any item we need to pick up a color for either creating
a brush or a pen. .NET framework has provided System.Drawing.Color
structure which contains 141 colors. That makes life pretty easy. But
there are some developers like me who have hard time corelating the color names
with what actually they look like.
To solve this probelm, we decided to come up with a chart that will display
all the colors along with the names used in Color
structure. The
crude approach could have been that we use a huge switch
statement
with each case
representing the colors defined in the structure.
But there is a very nice approach that we took. .NET framework procides a
very powerful feature called Reflection. All the colors in
System.Drawing.Color
structure are declared as
public
static
properties. So the idea is pretty simple.
- Get
Type
of System.Drawing.Color
strcuture.
- Call
GetProperties
method on Type
instance. Make
sure that you use the appropriate BindingFlags
attribute to get
only the properties that are of interest. In our case we are only interested in
public static
properties. Therefore we will use
BindingFlags.Public
, BindingFlags.Static
and
BindingFlags.DeclaredOnly
ORed together. The purpose of specifying
BindingFlags.DeclaredOnly
attribute is to get only the
static
properties that are declared only in this class only. We are
not interested in properties of any parent class or structure.
- Iterate through each item in
PropertyInfo
array value returned
by GetProperties
method. Call Name
property on
PropertyInfo
object to get the name of each color. And call
GetValue
method to get the actual value of Color
.
- Rest is just implementation detail and book keeping on how to arrange all
the colors on the bitmap and display it as a chart.
The complete code is attached with the article. Take a look at it for
details.
Color testColor = Color.AliceBlue;
Type colorType = testColor.GetType();
if (null != colorType)
{
PropertyInfo[] propInfoList =
colorType.GetProperties(BindingFlags.Static|BindingFlags.DeclaredOnly
|BindingFlags.Public);
int nNumProps = propInfoList.Length;
for (int i = 0; i < nNumRows; i++)
{
PropertyInfo propInfo = (PropertyInfo)propInfoList[nIdx];
Color color = (Color)propInfo.GetValue(null, null);
string strColorName = propInfo.Name;
}
}
The complete color chart is available at our web site at Complete Color
Chart.