How Can I Get a C# Variable's Name at Runtime?

Getting Variable Names with Reflection

In C#, variables may appear nameless in compiled Intermediate Language (IL) code. However, we can utilize reflection techniques to retrieve variable names by leveraging expression trees.

Consider the following example:

var someVar = 3;

Console.WriteLine(GetVariableName(someVar));

Our goal is to output "someVar".

Using Expression Trees

Reflection does not provide direct access to variable names. Instead, we can employ expression trees to create a closure that promotes the variable to a named scope. The following method achieves this:

public static string GetVariableName<T>(Expression<Func<T>> expr)
{
    var body = (MemberExpression)expr.Body;
    return body.Member.Name;
}

To use this method, we wrap the variable within a lambda expression:

Console.WriteLine(GetVariableName(() => someVar));

Note: This approach comes with a performance overhead due to object creation and heavy reflection usage.

C# 6.0 Alternative

With C# 6.0, the nameof keyword simplifies this process:

Console.WriteLine(nameof(someVar));

The nameof keyword provides a direct, lightweight way to retrieve variable names without the performance implications of the expression tree method.

The above is the detailed content of How Can I Get a C# Variable's Name at Runtime?. For more information, please follow other related articles on the PHP Chinese website!