[英]expression trees linq get value of a parameter?
AddOptional<tblObject>(x =>x.Title, objectToSend.SupplementaryData);
private static void AddOptional<TType>(Expression<Func<TType,string>> expr, Dictionary<string, string> dictionary)
{
string propertyName;
string propertyValue;
Expression expression = (Expression)expr;
while (expression.NodeType == ExpressionType.Lambda)
{
expression = ((LambdaExpression)expression).Body;
}
}
在上述代码中,我想获取属性标题的实际值,而不是属性名称的实际值,这可能吗?
private static void Main(string[] args)
{
CompileAndGetValue<tblObject>(x => x.Title, new tblObject() { Title = "test" });
}
private static void CompileAndGetValue<TType>(
Expression<Func<TType, string>> expr,
TType obj)
{
// you can still get name here
Func<TType, string> func = expr.Compile();
string propretyValue = func(obj);
Console.WriteLine(propretyValue);
}
但是,您必须意识到这可能会很慢。 您应该衡量它在您的情况下的性能。
如果您不喜欢传递对象:
private static void Main(string[] args)
{
var yourObject = new tblObject {Title = "test"};
CompileAndGetValue(() => yourObject.Title);
}
private static void CompileAndGetValue(
Expression<Func<string>> expr)
{
// you can still get name here
var func = expr.Compile();
string propretyValue = func();
Console.WriteLine(propretyValue);
}
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