将VB.NET代码移植到C＃时出现问题

Question

Currently I am trying to port some VB.NET code to C#.

The struct looks like this in VB.NET:

Public Structure sPos
    Dim x, y, z As Single
    Function getSectorY() As Single
        Return Math.Floor(y / 192 + 92)
    End Function
    Function getSectorX() As Single
        Return Math.Floor(x / 192 + 135)
    End Function
    Function getSectorXOffset() As Int32
        Return ((x / 192) - getSectorX() + 135) * 192 * 10
    End Function
    Function getSectorYOffset() As Int32
        Return ((y / 192) - getSectorY() + 92) * 192 * 10
    End Function
End Structure

C# Version of the struct:

    public struct sPos
    {
        public float x;
        public float y;
        public float z;
        public float getSectorY()
        {
            return (float)Math.Floor(y / 192 + 92);
        }
        public float getSectorX()
        {
            return (float)Math.Floor(x / 192 + 135);
        }
        public Int32 getSectorXOffset()
        {
            return (int)((x / 192) - getSectorX() + 135) * 192 * 10;
        }
        public Int32 getSectorYOffset()
        {
            return (int)((y / 192) - getSectorY() + 92) * 192 * 10;
        }
    }

Why do I have to cast the return values to float & int ? In the vb version I don't have to..

Thanks everyone.

Answer 1

Put a () after getXSectorOffset because it's a function?

example:

nullPointX = pictureBox1.Width / 2 - sectorsize - centerPos.getSectorXOffset() / 10 * sectorsize / 192;

Regarding the second question, you could avoid cast to float with this modification:

public float getSectorY()
    {
        return (float)Math.Floor(y / 192f + 92f);
    }

And sorry, you'll have to cast to int still. Unless you cast the x and getXOffset() to int during the function:

public Int32 getSectorXOffset()
    {
        return (((int)x / 192) - (int)getSectorX() + 135) * 192 * 10;
    }

Answer 2

Note that you shouldn't use "Dim" on class/structure level variables. Always use Public, Protected, Private etc.

Also note that division works differently in VB and C#. In VB, if you divide two integers like so:

Dim r As Double = 5/2

Then r will be a Double with value 2.5

In C# however, division with integers gives you integer results, 2 in this case.

Answer 3

如果您在VB代码中设置Option Strict On （您确实应该总是这样做），那么我认为您也需要在VB中强制转换返回值：Math.Floor（）返回Double，而不是Single，并且您应该真正告诉编译器您想失去该精度（这是C＃版本中的（浮点数）所做的事情），而不是让编译器在没有做出明智决定的情况下就放弃精度。