Finding the variable name passed to a function

Question

Let me use the following example to explain my question:

public string ExampleFunction(string Variable) {
    return something;
}

string WhatIsMyName = "         


        

Answer 1

Three ways:

1) Something without reflection at all:

GetParameterName1(new { variable });

public static string GetParameterName1(T item) where T : class
{
    if (item == null)
        return string.Empty;

    return item.ToString().TrimStart('{').TrimEnd('}').Split('=')[0].Trim();
}

2) Uses reflection, but this is way faster than other two.

GetParameterName2(new { variable });

public static string GetParameterName2(T item) where T : class
{
    if (item == null)
        return string.Empty;

    return typeof(T).GetProperties()[0].Name;
}

3) The slowest of all, don't use.

GetParameterName3(() => variable);

public static string GetParameterName3(Expression> expr)
{
    if (expr == null)
        return string.Empty;

    return ((MemberExpression)expr.Body).Member.Name;
}

To get a combo parameter name and value, you can extend these methods. Of course its easy to get value if you pass the parameter separately as another argument, but that's inelegant. Instead:

1)

public static string GetParameterInfo1(T item) where T : class
{
    if (item == null)
        return string.Empty;

    var param = item.ToString().TrimStart('{').TrimEnd('}').Split('=');
    return "Parameter: '" + param[0].Trim() +
           "' = " + param[1].Trim();
}

2)

public static string GetParameterInfo2(T item) where T : class
{
    if (item == null)
        return string.Empty;

    var param = typeof(T).GetProperties()[0];
    return "Parameter: '" + param.Name +
           "' = " + param.GetValue(item, null);
}

3)

public static string GetParameterInfo3(Expression> expr)
{
    if (expr == null)
        return string.Empty;

    var param = (MemberExpression)expr.Body;
    return "Parameter: '" + param.Member.Name +
           "' = " + ((FieldInfo)param.Member).GetValue(((ConstantExpression)param.Expression).Value);
}

1 and 2 are of comparable speed now, 3 is again sluggish.