Expression Tree

Expression Tree

Expression Tree 的一个例子

public static class ObjectionExtension
{
/// <summary>
/// 获取属性的名称
/// </summary>
/// <typeparam name="T">泛型</typeparam>
/// <typeparam name="TProperty">属性</typeparam>
/// <param name="t">对象</param>
/// <param name="expression">属性</param>
/// <returns>属性的名称</returns>
public static string GetPropertyName<T, TProperty>(this T t, Expression<Func<T, TProperty>> expression)
{
var memberExpression = expression.Body as MemberExpression;
if (memberExpression != null)
{
return memberExpression.Member.Name;
}
var paramExpression = expression.Body as ParameterExpression;
if (paramExpression != null)
{
return paramExpression.Name;
}
return string.Empty;
}

/// <summary>
/// 根据属性名获取属性值
/// </summary>
/// <typeparam name="T">对象类型</typeparam>
/// <param name="t">对象</param>
/// <param name="name">属性名</param>
/// <returns>属性的值</returns>
public static TProperty GetPropertyValue<T, TProperty>(this T t, Expression<Func<T, TProperty>> expression)
{
var func = expression.Compile();
var result = func(t);
return result;
}

/// <summary>
/// 根据属性名称设置属性的值
/// </summary>
/// <typeparam name="T">对象类型</typeparam>
/// <param name="t">对象</param>
/// <param name="name">属性名</param>
/// <param name="value">属性的值</param>
public static void SetPropertyValue<T>(this T t, Action<T> action)
{
action(t);
}

public static T As<T>(this object obj)
{
return default(T);
}
}