问题描述
我如何定义，我想在LINQ查询中使用的变量的lambdaexpression？
How can I define a lambdaexpression that I want to use in a linq query as a variable?
例如排序由listItems中的不同属性的通用列表时
For example when sorting a generic list by different properties of the listitems:
IList<SampleClass> list = new List<SampleClass>();
// Populate list
...
list.OrderBy(sampleclass => sampleclass.property1);
list.OrderBy(sampleclass => sampleclass.property2);
我想在一个变量和呼叫来定义lambda表达式（sampleclass => sampleclass.property1）
I would like to define the lambda expression (sampleclass => sampleclass.property1) in a variable and call:
// ??? define expression in a variable ???
Expression expression = sampleclass => sampleclass.property1;
// Sort list by variable expression
list.OrderBy(expression);
在此先感谢
托比
Thanks in advanceTobi
推荐答案
您可以使用 Func键之一重载（的准确）：
You can use one of Func overloads (Func<T, TResult> precisely):
Func<SampleClass, PropertyType> expr = sampleclass => sampleclass.property1;
list.OrderBy(expr);
属性类型存储为变量的类型 property1 在 SampleClass 。如果是例如字符串，你可以使用 Func键< SampleClass，串方式>
PropertyType is the type of variable stored as property1 in your SampleClass. If it was for example string, you would use Func<SampleClass, string>.
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