C# 3.0 Cookbook, 3rd Edition

3.12. Returning Multiple Items from a Method

Problem

In many cases, a single return value for a method is not enough. You need a way to return more than one item from a method.

Solution

Use the out keyword on parameters that will act as return parameters. The following method accepts an inputShape parameter and calculates height, width, and depth from that value:

	    public void ReturnDimensions(int inputShape,
	                                 out int height,
	                                 out int width,
	                                 out int depth)
	   {
	        height = 0;
	        width = 0;
	        depth = 0;

	        // Calculate height, width, and depth from the inputShape value.
	    }

This method would be called in the following manner:

	    // Declare output parameters.
	    int height;
	    int width;
	    int depth;

	    // Call method and return the height, width, and depth.
	    Obj.ReturnDimensions(1, out height, out width, out depth);

Another method is to return a class or structure containing all the return values. The previous method has been modified to return a structure instead of using out arguments:

	    public Dimensions ReturnDimensions(int inputShape)
	    {
	        // The default ctor automatically defaults this structure's members to 0.
	        Dimensions objDim = new Dimensions( );

	        // Calculate objDim.Height, objDim.Width, objDim.Depth from the inputShape
	value.

	        return objDim;
	}

where Dimensions is defined as follows:

	    public struct Dimensions
	    {
	        public int Height;
	        public int Width;
	        public int Depth;
	    }

This method would now be called in this manner:

	    // Call method and return the height, width, and depth.
	    Dimensions objDim = obj.ReturnDimensions(1);

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