StringBuilder AppendFormat 按照自己的方式格式化

最新推荐文章于 2024-08-14 23:47:56 发布

原创最新推荐文章于 2024-08-14 23:47:56 发布 · 1.5k 阅读

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#string #object #class #system #null

本文介绍了一个自定义格式提供者BoldInt32s的实现，该类实现了IFormatProvider和ICustomFormatter接口，能够根据不同类型的输入返回带有HTML标签的格式化字符串。示例代码展示了如何使用StringBuilder结合此类进行格式化输出。

using System;
using System.Text;
using System.Threading;

public static class Program {
   public static void Main() {
      StringBuilder sb = new StringBuilder();
      sb.AppendFormat(new BoldInt32s(), "{0} {1} {2:M}", "Jeff", 123, DateTime.Now);
      Console.WriteLine(sb);
   }
}

internal sealed class BoldInt32s : IFormatProvider, ICustomFormatter {
   public Object GetFormat(Type formatType) {
      if (formatType == typeof(ICustomFormatter)) return this;
      return Thread.CurrentThread.CurrentCulture.GetFormat(formatType);
   }

public String Format(String format, Object arg, IFormatProvider formatProvider) {
String s;

IFormattable formattable = arg as IFormattable;

if (formattable == null) s = arg.ToString();
else s = formattable.ToString(format, formatProvider);

      if (arg.GetType() == typeof(Int32))
         return "<B>" + s + "</B>";
     if (arg.GetType() == typeof(String))
         return "<p>" + s + "</p>";
      return s;
   }
}