[英]Programmatically get a brush from the Brushes class?
我有一個屬性,允許將已知顏色的字符串名稱發送到我的控件。 酒店僅接受正確的已知顏色名稱,如“紅色”或“藍色”
private KnownColor _UseColor = KnownColor.Red;
/// <summary>
/// Gets or sets the name of the colour
/// </summary>
public string ColorName
{
get
{
return this._UseColor.ToString();
}
set
{
if (Enum.IsDefined(typeof(KnownColor), value))
this._UseColour = (KnownColor)Enum.Parse(typeof(KnownColor), value);
}
}
我想要做的是使用這個_UseColour
枚舉從.NET中的靜態Brushes類中選擇一個現有的畫筆,就像這樣
Brush sysBrush = Brushes.FromKnownColor(this._UseColor);
e.Graphics.FillRectangle(sysBrush, 0, 0, 10, 10);
而不是在控件被繪制時創建一個新的畫筆
using (SolidBrush brsh = new SolidBrush(Color.FromKnownColor(this._UseColor)))
e.Graphics.FillRectangle(brsh, 0, 0, 10, 10);
有誰知道這是否可能,或者我每次都要創建一個新畫筆?
Brushes.FromKnownColor
不是Brushes
類中的方法
為什么不創建一次刷子並將其緩存以供以后使用?
在你的主要課程中:
private KnownColor _UseColor = KnownColor.Red;
/// <summary>
/// Gets or sets the name of the colour
/// </summary>
public string ColorName
{
get
{
return this._UseColor.ToString();
}
set
{
if (Enum.IsDefined(typeof(KnownColor), value))
this._UseColour = (KnownColor)Enum.Parse(typeof(KnownColor), value);
}
}
private Dictionary<string, Brush> _knownBrushes = new Dictionary<string, Brush>();
public Brush ColorBrush
{
get
{
if (!_knownBrushes.ContainsKey(_UseColor)) {
_knownBrushes[_UseColor] = new SolidBrush(Color.FromKnownColor(this._UseColor));
}
return _knownBrushes[_UseColor];
}
}
那就像..
e.Graphics.FillRectangle(ColorBrush, 0, 0, 10, 10);
var properties = typeof (Brushes).GetProperties();
var property = properties.FirstOrDefault(p => p.Name == "Red");
var brush = property.GetValue(null, null); // Contains Brushes.Red
領域:
PropertyInfo[] _properties = typeof (Brushes).GetProperties();
static Brush GetKnownBrush(string knownColorName)
{
var property = _properties.FirstOrDefault(p => p.Name == knownColorName);
var brush = property.GetValue(null, null);
return brush;
}
用法:
var knownBrush = GetKnownBrush(ColorName);
Brush KnownBrush
{
get
{
var property = _properties.FirstOrDefault(p => p.Name == ColorName);
var brush = property.GetValue(null, null);
return brush;
}
}
用法:
var knownBrush = KnownBrush;
您還可以將經常使用的畫筆存儲在字典中,以避免反射操作。
如果您想要一種可以通過顏色查找畫筆的解決方案,即使顏色可能沒有已知名稱,您也可以創建使用該顏色的字典:
void Main()
{
var brush = KnownBrush(Color.FromArgb(255, 0, 0));
brush.Dump();
}
private static Dictionary<Tuple<byte, byte, byte, byte>, SolidBrush> _KnownBrushes;
public static SolidBrush KnownBrush(Color color)
{
if (_KnownBrushes == null)
{
_KnownBrushes = new Dictionary<Tuple<byte, byte, byte, byte>, SolidBrush>();
foreach (var propertyInfo in typeof(Brushes).GetProperties())
{
if (propertyInfo.PropertyType == typeof(Brush))
{
var brush = propertyInfo.GetValue(null) as SolidBrush; // not a typo
if (brush != null)
_KnownBrushes[Tuple.Create(brush.Color.R, brush.Color.G, brush.Color.B, brush.Color.A)] = brush;
}
}
}
SolidBrush result;
_KnownBrushes.TryGetValue(Tuple.Create(color.R, color.G, color.B, color.A), out result);
return result;
}
其他答案很復雜。 這是一個單行將字符串“purple”轉換為純色畫筆:
new SolidColorBrush((Color)ColorConverter.ConvertFromString("purple"))
記住using System.Windows.Media;
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