如何动态调用的TryParse？ [英] How to call TryParse dynamically?

问题描述

有没有办法的TryParse 动态调用？有些类型的：

Is there a way to call TryParse dynamically? Some kind of:

public static bool TryParse<T>(string toConvert, out T result)

当然，人们可以使用Typeonverters这一点。然而，一个无效的转换将导致异常，我想摆脱这一点。

Of course one can use Typeonverters for this. However, an invalid conversion will result in an exception and I want to get rid of this.

推荐答案

您可以动态地使用反射调用的TryParse 方法。这样你就不会得到一个时间，如果转换失败消费异常。

You could call the TryParse method dynamically using Reflection. This way you won't get a time consuming Exception if the conversion fails.

此方法是这样的 之一。

    //Try Parse using Reflection
public static bool TryConvertValue<T>(string stringValue, out T convertedValue)
{
    var targetType = typeof(T);
    if (targetType == typeof(string))
    {
        convertedValue = (T)Convert.ChangeType(stringValue, typeof(T));
        return true;
    }
        var nullableType = targetType.IsGenericType &&
                       targetType.GetGenericTypeDefinition() == typeof (Nullable<>);
    if (nullableType)
    {
        if (string.IsNullOrEmpty(stringValue))
        {
            convertedValue = default(T);
            return true;
        }
            targetType = new NullableConverter(targetType).UnderlyingType;
    }

    Type[] argTypes = { typeof(string), targetType.MakeByRefType() };
    var tryParseMethodInfo = targetType.GetMethod("TryParse", argTypes);
    if (tryParseMethodInfo == null)
    {
        convertedValue = default(T);
        return false;
    }

    object[] args = { stringValue, null };
    var successfulParse = (bool)tryParseMethodInfo.Invoke(null, args);
    if (!successfulParse)
    {
        convertedValue = default(T);
        return false;
    }

    convertedValue = (T)args[1];
    return true;
}

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