Can i have different type of objects in a C# *using* block ?

Question

using (Font font3 = new Font("Arial", 10.0f), 
           font4 = new Font("Arial", 10.0f))
{
    // Use font3 and font4.
}

I know that multiple objects of same type can be used inside a using clause.

Cant i use different types of objects inside the using clause?

Well i tried but although they were different names and different objects, they acted the same = had the same set of methods

Is there any other way to use the using class with different types?

If not, what is the most appropriate way to use it?

Answer 1

using(Font f1 = new Font("Arial",10.0f))
using (Font f2 = new Font("Arial", 10.0f))
using (Stream s = new MemoryStream())
{

}

Like so?

Answer 2

No you can't do it this way, but you can nest the using blocks.

using (Font font3 = new Font("Arial", 10.0f))
{ 
    using (Font font4 = new Font("Arial", 10.0f))
    {
        // Use font3 and font4.
    }
}

or as others said, but I'd not recommend it that way because of readability.

using(Font font3 = new Font("Arial", 10.0f))
using(Font font4 = new Font("Arial", 10.0f))
{
    // use font3 and font4
}

Answer 3

You can only have a single type of object initialized in each using block. You can nest those as much as you want, however:

using (Font font3 = new Font("Arial", 10.0f))
{
    using (Brush b4 = new Brush())
    {

    }
}

Answer 4

You can nest them:

using (Font font3 = new Font("Arial", 10.0f))
using (font4 = new Font("Arial", 10.0f))
{
    // Use font3 and font4.
}

They should dispose in reverse order (font4 first).

EDIT:

This is exactly the same as:

using (Font font3 = new Font("Arial", 10.0f))
{
    using (font4 = new Font("Arial", 10.0f))
    {
        // Use font3 and font4.
    }
}

Answer 5

You can stack using statements to accomplish this:

using(Font font3 = new Font("Arial", 10.0f))
using(Font font4 = new Font("Arial", 10.0f))
{
    // use font3 and font4
}

Answer 6

You can comma-delimit items of the same type - well, all I know is the compiler doesn't complain. You can also stack using () statements (use one set of brackets {}) of different types.

http://adamhouldsworth.blogspot.com/2010/02/things-you-dont-know.html

Answer 7

The using statement purpose is to guarantee that the acquired resources are explicitly disposed by a call to Dispose method provided by the IDisposable interface. The specification does not allow you to acquire resources of different types inside a single using statement but having the first sentence in mind you can write this perfectly valid code in terms of the compiler.

using (IDisposable d1 = new Font("Arial", 10.0f),
    d2 = new Font("Arial", 10.0f), 
    d3 = new MemoryStream())
{
    var stream1 = (MemoryStream)d3;
    stream1.WriteByte(0x30);
}

However, I'm not recommending this and I consider it abusive, so this answer is just to state that you can hack around it but you probably should not.