受到Charlie Brown在这里发布的解决方案的启发，我使用反射创建了一个通用的TryParse，可以选择输出解析后的值:
/// <summary>
/// Tries to convert the specified string representation of a logical value to
/// its type T equivalent. A return value indicates whether the conversion
/// succeeded or failed.
/// </summary>
/// <typeparam name="T">The type to try and convert to.</typeparam>
/// <param name="value">A string containing the value to try and convert.</param>
/// <param name="result">If the conversion was successful, the converted value of type T.</param>
/// <returns>If value was converted successfully, true; otherwise false.</returns>
public static bool TryParse<T>(string value, out T result) where T : struct {
var tryParseMethod = typeof(T).GetMethod("TryParse", BindingFlags.Static | BindingFlags.Public, null, new [] { typeof(string), typeof(T).MakeByRefType() }, null);
var parameters = new object[] { value, null };
var retVal = (bool)tryParseMethod.Invoke(null, parameters);
result = (T)parameters[1];
return retVal;
}
/// <summary>
/// Tries to convert the specified string representation of a logical value to
/// its type T equivalent. A return value indicates whether the conversion
/// succeeded or failed.
/// </summary>
/// <typeparam name="T">The type to try and convert to.</typeparam>
/// <param name="value">A string containing the value to try and convert.</param>
/// <returns>If value was converted successfully, true; otherwise false.</returns>
public static bool TryParse<T>(string value) where T : struct {
T throwaway;
var retVal = TryParse(value, out throwaway);
return retVal;
}
它可以这样被称为:
string input = "123";
decimal myDecimal;
bool myIntSuccess = TryParse<int>(input);
bool myDecimalSuccess = TryParse<decimal>(input, out myDecimal);
更新:
也感谢我非常喜欢的YotaXP的解决方案，我创建了一个不使用扩展方法但仍然有一个单例的版本，最大限度地减少了反射的需要:
/// <summary>
/// Provides some extra parsing functionality for value types.
/// </summary>
/// <typeparam name="T">The value type T to operate on.</typeparam>
public static class TryParseHelper<T> where T : struct {
private delegate bool TryParseFunc(string str, out T result);
private static TryParseFunc tryParseFuncCached;
private static TryParseFunc tryParseCached {
get {
return tryParseFuncCached ?? (tryParseFuncCached = Delegate.CreateDelegate(typeof(TryParseFunc), typeof(T), "TryParse") as TryParseFunc);
}
}
/// <summary>
/// Tries to convert the specified string representation of a logical value to
/// its type T equivalent. A return value indicates whether the conversion
/// succeeded or failed.
/// </summary>
/// <param name="value">A string containing the value to try and convert.</param>
/// <param name="result">If the conversion was successful, the converted value of type T.</param>
/// <returns>If value was converted successfully, true; otherwise false.</returns>
public static bool TryParse(string value, out T result) {
return tryParseCached(value, out result);
}
/// <summary>
/// Tries to convert the specified string representation of a logical value to
/// its type T equivalent. A return value indicates whether the conversion
/// succeeded or failed.
/// </summary>
/// <param name="value">A string containing the value to try and convert.</param>
/// <returns>If value was converted successfully, true; otherwise false.</returns>
public static bool TryParse(string value) {
T throwaway;
return TryParse(value, out throwaway);
}
}
这样叫它:
string input = "987";
decimal myDecimal;
bool myIntSuccess = TryParseHelper<int>.TryParse(input);
bool myDecimalSuccess = TryParseHelper<decimal>.TryParse(input, out myDecimal);
