I am encountering a problem which is how do I convert input strings like "RED" to the actual Color type Color.Red
in C#. Is there a good way to do this?
I could think of using a switch开发者_JS百科 statement and cases statement for each color type but I don't think that is clever enough.
Color red = Color.FromName("Red");
The MSDN doesn't say one way or another, so there's a good chance that it is case-sensitive. (UPDATE: Apparently, it is not.)
As far as I can tell, ColorTranslator.FromHtml
is also.
If Color.FromName
cannot find a match, it returns new Color(0,0,0);
If ColorTranslator.FromHtml
cannot find a match, it throws an exception.
UPDATE:
Since you're using Microsoft.Xna.Framework.Graphics.Color, this gets a bit tricky:
using XColor = Microsoft.Xna.Framework.Graphics.Color;
using CColor = System.Drawing.Color;
CColor clrColor = CColor.FromName("Red");
XColor xColor = new XColor(clrColor.R, clrColor.G, clrColor.B, clrColor.A);
System.Drawing.Color myColor = System.Drawing.ColorTranslator.FromHtml("Red");
(Use my method if you want to accept HTML-style hex colors.)
(It would really have been nice if you'd mentioned which Color
type you were interested in to start with...)
One simple way of doing this is to just build up a dictionary via reflection:
public static class Colors
{
private static readonly Dictionary<string, Color> dictionary =
typeof(Color).GetProperties(BindingFlags.Public |
BindingFlags.Static)
.Where(prop => prop.PropertyType == typeof(Color))
.ToDictionary(prop => prop.Name,
prop => (Color) prop.GetValue(null, null)));
public static Color FromName(string name)
{
// Adjust behaviour for lookup failure etc
return dictionary[name];
}
}
That will be relatively slow for the first lookup (while it uses reflection to find all the properties) but should be very quick after that.
If you want it to be case-insensitive, you can pass in something like StringComparer.OrdinalIgnoreCase
as an extra argument in the ToDictionary
call. You can easily add TryParse
etc methods should you wish.
Of course, if you only need this in one place, don't bother with a separate class etc :)
It depends on what you're looking for, if you need System.Windows.Media.Color (like in WPF) it's very easy:
System.Windows.Media.Color color = (Color)System.Windows.Media.ColorConverter.ConvertFromString("Red");//or hexadecimal color, e.g. #131A84
Since the OP mentioned in a comment that he's using Microsoft.Xna.Framework.Graphics.Color
rather than System.Drawing.Color
you can first create a System.Drawing.Color then convert it to a Microsoft.Xna.Framework.Graphics.Color
public static Color FromName(string colorName)
{
System.Drawing.Color systemColor = System.Drawing.Color.FromName(colorName);
return new Color(systemColor.R, systemColor.G, systemColor.B, systemColor.A); //Here Color is Microsoft.Xna.Framework.Graphics.Color
}
For transferring colors via xml-strings I've found out:
Color x = Color.Red; // for example
String s = x.ToArgb().ToString()
... to/from xml ...
Int32 argb = Convert.ToInt32(s);
Color red = Color.FromArgb(argb);
This worked nicely for my needs ;) Hope someone can use it....
public static Color FromName(String name)
{
var color_props= typeof(Colors).GetProperties();
foreach (var c in color_props)
if (name.Equals(c.Name, StringComparison.OrdinalIgnoreCase))
return (Color)c.GetValue(new Color(), null);
return Colors.Transparent;
}
The simplest way:
string input = null;
Color color = Color.White;
TextBoxText_Changed(object sender, EventsArgs e)
{
input = TextBox.Text;
}
Button_Click(object sender, EventsArgs e)
{
color = Color.FromName(input)
}
The following can generate a color from name, hex, or known name.
Color beige = StringToColor("Beige");
Color purple = StringToColor("#800080");
Color window = StringToColor("Window");
public static Color StringToColor(string colorStr)
{
TypeConverter cc = TypeDescriptor.GetConverter(typeof(Color));
var result = (Color)cc.ConvertFromString(colorStr);
return result;
}
The snippet was taken from Jo Albahari's C# in a Nutshell.
I've used something like this before:
public static T CreateFromString<T>(string stringToCreateFrom) {
T output = Activator.CreateInstance<T>();
if (!output.GetType().IsEnum)
throw new IllegalTypeException();
try {
output = (T) Enum.Parse(typeof (T), stringToCreateFrom, true);
}
catch (Exception ex) {
string error = "Cannot parse '" + stringToCreateFrom + "' to enum '" + typeof (T).FullName + "'";
_logger.Error(error, ex);
throw new IllegalArgumentException(error, ex);
}
return output;
}
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