我的转换扩展，允许你做:

int i = myString.To<int>();

这是在TheSoftwareJedi.com上发布的

public static T To<T>(this IConvertible obj)
{
  return (T)Convert.ChangeType(obj, typeof(T));
}

public static T ToOrDefault<T>
             (this IConvertible obj)
{
    try
    {
        return To<T>(obj);
    }
    catch
    {
        return default(T);
    }
}

public static bool ToOrDefault<T>
                    (this IConvertible obj,
                     out T newObj)
{
    try
    {
        newObj = To<T>(obj); 
        return true;
    }
    catch
    {
        newObj = default(T); 
        return false;
    }
}

public static T ToOrOther<T>
                       (this IConvertible obj,
                       T other)
{
  try
  {
      return To<T>obj);
  }
  catch
  {
      return other;
  }
}

public static bool ToOrOther<T>
                         (this IConvertible obj,
                         out T newObj,
                         T other)
{
    try
    {
        newObj = To<T>(obj);
        return true;
    }
    catch
    {
        newObj = other;
        return false;
    }
}

public static T ToOrNull<T>
                      (this IConvertible obj)
                      where T : class
{
    try
    {
        return To<T>(obj);
    }
    catch
    {
        return null;
    }
}

public static bool ToOrNull<T>
                  (this IConvertible obj,
                  out T newObj)
                  where T : class
{
    try
    {
        newObj = To<T>(obj);
        return true;
    }
    catch
    {
        newObj = null;
        return false;
    }
}

您可以在失败时请求default(调用空白构造函数或“0”作为数字)，指定一个“default”值(我称之为“other”)，或请求null(其中T: class)。我还提供了两个静默异常模型和一个典型的TryParse模型，该模型返回一个bool值，指示所采取的操作，一个out参数保存新值。 我们的代码可以这样做

int i = myString.To<int>();
string a = myInt.ToOrDefault<string>();
//note type inference
DateTime d = myString.ToOrOther(DateTime.MAX_VALUE);
double d;
//note type inference
bool didItGiveDefault = myString.ToOrDefault(out d);
string s = myDateTime.ToOrNull<string>();

我不能让Nullable类型非常干净地滚入整个东西。我试了大约20分钟才认输。

这个还没有完全烤熟因为我们今天早上才想到。它将为Type生成一个完整的类定义。当您有一个大型类，想要创建一个子集或完整定义，但无法访问它的情况下非常有用。例如，将对象存储在数据库中等等。

public static class TypeExtensions
{
    public static string GenerateClassDefinition(this Type type)
    {
        var properties = type.GetFields();
        var sb = new StringBuilder();
        var classtext = @"private class $name
        {
         $props}";

        foreach (var p in GetTypeInfo(type))
        {
            sb.AppendFormat("  public {0} {1} ", p.Item2, p.Item1).AppendLine(" { get; set; }");
        }

        return classtext.Replace("$name", type.Name).Replace("$props", sb.ToString());
    }

    #region Private Methods
    private static List<Tuple<string, string>> GetTypeInfo(Type type)
    {
        var ret = new List<Tuple<string, string>>();
        var fields = type.GetFields();
        var props = type.GetProperties();

        foreach(var p in props) ret.Add(new Tuple<string, string>(p.Name, TranslateType(p.PropertyType)));    
        foreach(var f in fields) ret.Add(new Tuple<string, string>(f.Name, TranslateType(f.FieldType)));

        return ret;
    }


    private static string TranslateType(Type input)
    {
        string ret;

        if (Nullable.GetUnderlyingType(input) != null)
        {
            ret = string.Format("{0}?", TranslateType(Nullable.GetUnderlyingType(input)));
        }
        else
        {
            switch (input.Name)
            {
                case "Int32": ret = "int"; break;
                case "Int64": ret = "long"; break;
                case "IntPtr": ret = "long"; break;
                case "Boolean": ret = "bool"; break;
                case "String":
                case "Char":
                case "Decimal":
                    ret = input.Name.ToLower(); break;
                default: ret = input.Name; break;
            }
        }

        return ret;
    }
    #endregion
}

使用示例:

Process.GetProcesses().First().GetType().GenerateClassDefinition();

如果使用linqpad，变得更加方便:

Process.GetProcesses().First().GetType().GenerateClassDefinition().Dump();

我今天刚刚在博客上写了这个。它是INotifyPropertyChanged属性周围的强类型响应式包装器。

GetPropertyValues返回一个IObservable<T>的值，当它们改变时，从当前值开始。如果忽略当前值，可以对结果调用Skip(1)。

用法如下:

IObservable<int> values = viewModel.GetPropertyValues(x => x.IntProperty);

实现:

public static class NotifyPropertyChangeReactiveExtensions
{
    // Returns the values of property (an Expression) as they change, 
    // starting with the current value
    public static IObservable<TValue> GetPropertyValues<TSource, TValue>(
        this TSource source, Expression<Func<TSource, TValue>> property)
        where TSource : INotifyPropertyChanged
    {
        MemberExpression memberExpression = property.Body as MemberExpression;

        if (memberExpression == null)
        {
            throw new ArgumentException(
                "property must directly access a property of the source");
        }

        string propertyName = memberExpression.Member.Name;

        Func<TSource, TValue> accessor = property.Compile();

        return source.GetPropertyChangedEvents()
            .Where(x => x.EventArgs.PropertyName == propertyName)
            .Select(x => accessor(source))
            .StartWith(accessor(source));
    }

    // This is a wrapper around FromEvent(PropertyChanged)
    public static IObservable<IEvent<PropertyChangedEventArgs>>
        GetPropertyChangedEvents(this INotifyPropertyChanged source)
    {
        return Observable.FromEvent<PropertyChangedEventHandler, 
            PropertyChangedEventArgs>(
            h => new PropertyChangedEventHandler(h),
            h => source.PropertyChanged += h,
            h => source.PropertyChanged -= h);
    }
}

这一次是为了使UriBuilder在处理查询参数时更加友好。

    /// <summary>
    /// Adds the specified query parameter to the URI builder.
    /// </summary>
    /// <param name="builder">The builder.</param>
    /// <param name="parameterName">Name of the parameter.</param>
    /// <param name="value">The URI escaped value.</param>
    /// <returns>The final full query string.</returns>
    public static string AddQueryParam(this UriBuilder builder, string parameterName, string value)
    {
        if (parameterName == null)
            throw new ArgumentNullException("parameterName");

        if (parameterName.Length == 0)
            throw new ArgumentException("The parameter name is empty.");

        if (value == null)
            throw new ArgumentNullException("value");

        if (value.Length == 0)
            throw new ArgumentException("The value is empty.");

        if (builder.Query.Length == 0)
        {
            builder.Query = String.Concat(parameterName, "=", value);
        }
        else if
            (builder.Query.Contains(String.Concat("&", parameterName, "="))
            || builder.Query.Contains(String.Concat("?", parameterName, "=")))
        {
            throw new InvalidOperationException(String.Format("The parameter {0} already exists.", parameterName));
        }
        else
        {
            builder.Query = String.Concat(builder.Query.Substring(1), "&", parameterName, "=", value);
        }

        return builder.Query;
    }

灵感来自弦。IsNullOrEmpty

要验证给定的List为空或空

public static bool IsNullOrEmpty<TSource>(this List<TSource> src)
{            
    return (src == null || src.Count == 0);
}

这个是验证给定的两个文件和属性

public static bool Compare(this FileInfo f1, FileInfo f2, string propertyName)
{
    try
    {
        PropertyInfo p1 = f1.GetType().GetProperty(propertyName);
        PropertyInfo p2 = f2.GetType().GetProperty(propertyName);

        if (p1.GetValue(f1, null) == p2.GetValue(f1, null))
            return true;
    }
    catch (Exception ex)
    {
        return false;
    }
    return false;
}

像这样使用它

FileInfo fo = new FileInfo("c:\\netlog.txt");
FileInfo f1 = new FileInfo("c:\\regkey.txt");

fo.compare(f1, "CreationTime");

我还没有看到任何关于这个问题的答案…

public static string[] Split(this string value, string regexPattern)
{
    return value.Split(regexPattern, RegexOptions.None);
}

public static string[] Split(this string value, string regexPattern, 
    RegexOptions options)
{
    return Regex.Split(value, regexPattern, options);
}

用法:

var obj = "test1,test2,test3";
string[] arrays = obj.Split(",");