我的类应该实现哪种接口或方法以在Console.WriteLine中打印我想要的内容？

Question

I have an object of class F. I want to output the contents of the object using Console.WriteLine for quick and dirty status updates like this:

Console.WriteLine(objectF);

This prints out only the name of the class to the console:

F

I want to overload this somehow so that I can instead print out some useful information about the object and its properties.

I have a workaround already: To overload the ToString method in my class and then call: Console.WriteLine(objectF.ToString());

But I would rather have the simpler syntax. Any ideas?

Answer 1

Console.WriteLine(objectF)

Should work, if you overloaded ToString . When the framework needs to convert an object to a string representation, it invokes ToString .

public override string ToString()
{
    // replace the line below with your code
    return base.ToString();
}

Answer 2

You should override ToString() though in some situations you may just find the following code useful:

public static class ObjectUtility
{
    public static string ToDebug(this object obj)
    {
        if (obj == null)
            return "<null>";

        var type = obj.GetType();
        var props = type.GetProperties();

        var sb = new StringBuilder(props.Length * 20 + type.Name.Length);
        sb.Append(type.Name);
        sb.Append("\r\n");

        foreach (var property in props)
        {
            if (!property.CanRead)
                continue;
            // AppendFormat defeats the point
            sb.Append(property.Name);
            sb.Append(": ");
            sb.Append(property.GetValue(obj, null));
            sb.Append("\r\n");
        }

        return sb.ToString();
    }
}

Usage is to simply include the namespace containing ObjectUtility and then...

var f = new F();
Console.WriteLine(f.ToDebug());

The reflection usage above isn't very good for high performance code so don't use it in a production scenario where high performance is desired.

Answer 3

I would continue to use ToString(). That's its purpose for existing. Also, unless you have a format string, you can just write:

Console.WriteLine(objectF)

Answer 4

I found the cause of my problem. I had neglected to define my implementation of ToString() as an override . The correct syntax is:

public override string ToString()
{
   ///Do stuff...
   return string;
}

Thanks to the posters below who put me on the right track