如何将RGBA css颜色格式转换为十六进制格式

Question

在我的硒代码中，我需要验证颜色代码是＃192856的背景。但是当我得到那个元素的CSS属性时，它给了我rgba格式的颜色。现在我需要获取十六进制值本身的值。我怎样才能做到这一点？

quickLinkstab.GetCssValue("background-color") 

上面给出了rgba值“rgba（25,40,86,1）”的值。有什么办法可以将它转换回十六进制？或者我可以在Hex中获得价值？

我也尝试下面的代码

string colorcode = menuColor; 
     int argb = Int32.Parse(colorcode.Replace("#", ""), NumberStyles.HexNumber); 
     Color clr = Color.FromArgb(argb); 


     int r = Convert.ToInt16(clr.R); 
     int g = Convert.ToInt16(clr.G); 
     int b = Convert.ToInt16(clr.B); 
     int a = Convert.ToInt16(clr.A); 
     string x = string.Format("rgba({0}, {1}, {2}, {3});", r, g, b,a); 

但这一个是给我价值等， “RGBA（25，40，86，0）;” 。 “a”值的差异。像我的代码给我0为“一”，但cssvalue为1

我更期待对越来越十六进制数值直接或如果没有可能再转换RGBA为十六进制的解决方案。

Answer 1

这应该可以做到。

public static string ConvertRgbaToHex(string rgba) 
{ 
    if (!Regex.IsMatch(rgba, @"rgba\((\d{1,3},\s*){3}(0(\.\d+)?|1)\)")) 
      throw new FormatException("rgba string was in a wrong format"); 

    var matches = Regex.Matches(rgba, @"\d+"); 
    StringBuilder hexaString = new StringBuilder("#"); 

    for(int i = 0; i < matches.Count - 1; i++) 
    { 
     int value = Int32.Parse(matches[i].Value); 

     hexaString.Append(value.ToString("X")); 
    } 

    return hexaString.ToString(); 
} 

测试用例：

public class Program 
{ 
    static void Main(string[] args) 
    { 
     // Output: #192856 
     Console.WriteLine(ConvertRgbaToHex("rgba(25, 40, 86, 1)")); 

     Console.Read(); 
    } 

    public static string ConvertRgbaToHex(string rgba) 
    { 
     if (!Regex.IsMatch(rgba, @"rgba\((\d{1,3},\s*){3}(0(\.\d+)?|1)\)")) 
       throw new FormatException("rgba string was in a wrong format"); 

     var matches = Regex.Matches(rgba, @"\d+"); 
     StringBuilder hexaString = new StringBuilder("#"); 

     for(int i = 0; i < matches.Count - 1; i++) 
     { 
      int value = Int32.Parse(matches[i].Value); 

      hexaString.Append(value.ToString("X")); 
     } 

     return hexaString.ToString(); 
    } 
} 

Answer 2

1. 使用System.Drawing.ColorTranslator

   string htmlColor = ColorTranslator.ToHtml(myColor);

2. 使用的String.Format

   String.Format("#{0:X2}{1:X2}{2:X2}", colorValue.R,colorValue.G,colorValue.B);

Answer 3

下面的代码覆盖十六进制格式，RGB格式和RGBA格式。

public static class ColorHelper 
{ 
    public static Color ParseColor(string cssColor) 
    { 
     cssColor = cssColor.Trim(); 

     if (cssColor.StartsWith("#")) 
     { 
      return ColorTranslator.FromHtml(cssColor); 
     } 
     else if (cssColor.StartsWith("rgb")) //rgb or argb 
     { 
      int left = cssColor.IndexOf('('); 
      int right = cssColor.IndexOf(')'); 

      if (left < 0 || right < 0) 
       throw new FormatException("rgba format error"); 
      string noBrackets = cssColor.Substring(left + 1, right - left - 1); 

      string[] parts = noBrackets.Split(','); 

      int r = int.Parse(parts[0], CultureInfo.InvariantCulture); 
      int g = int.Parse(parts[1], CultureInfo.InvariantCulture); 
      int b = int.Parse(parts[2], CultureInfo.InvariantCulture); 

      if (parts.Length == 3) 
      { 
       return Color.FromArgb(r, g, b); 
      } 
      else if (parts.Length == 4) 
      { 
       float a = float.Parse(parts[3], CultureInfo.InvariantCulture); 
       return Color.FromArgb((int)(a * 255), r, g, b); 
      } 
     } 
     throw new FormatException("Not rgb, rgba or hexa color string"); 
    } 
} 

预期结果：

[TestClass] 
public class ColorParserTest 
{ 
    [TestMethod] 
    public void TestParseColorRGB() 
    { 
     Color c = ColorHelper.ParseColor("rgb(110,120,130)"); 

     Assert.AreEqual(110, c.R); 
     Assert.AreEqual(120, c.G); 
     Assert.AreEqual(130, c.B); 
     Assert.AreEqual(255, c.A); 
    } 

    [TestMethod] 
    public void TestParseColorRGBA() 
    { 
     Color c = ColorHelper.ParseColor("rgba(110,120,130,0.5)"); 

     Assert.AreEqual(110, c.R); 
     Assert.AreEqual(120, c.G); 
     Assert.AreEqual(130, c.B); 
     Assert.AreEqual(127, c.A); 
    } 

    [TestMethod] 
    public void TestParseColorHexa() 
    { 
     Color c = ColorHelper.ParseColor("#192856"); 

     Assert.AreEqual(25, c.R); 
     Assert.AreEqual(40, c.G); 
     Assert.AreEqual(86, c.B); 
     Assert.AreEqual(255, c.A); 
    } 
}