CODEWITHSUNDEEP
c#objectdynamiccasting
Chris
Chris

Reputation: 701

How to set a dynamic object to the correct type

This is my function to move the scrollbars (I have horizontal one and a vertical one)

    private void moveTheScroll(object sbar, int scrollDiff)
    {
        if (sbar is HScrollBar)
        {
            int newScrollvalue = ((HScrollBar)sbar).Value + scrollDiff;
            if (((HScrollBar)sbar).Minimum < newScrollvalue &&
                newScrollvalue < ((HScrollBar)sbar).Maximum)
                ((HScrollBar)sbar).Value = newScrollvalue;
        }
        else if (sbar is VScrollBar)
        {
            int newScrollvalue = ((VScrollBar)sbar).Value + scrollDiff;
            if (((VScrollBar)sbar).Minimum < newScrollvalue &&
                newScrollvalue < ((VScrollBar)sbar).Maximum)
            ((VScrollBar)sbar).Value = scrollDiff;
        }
    }

Is there a way to to not typecast the object every single time I want to use it and make an alias instead? Something similar to this (this doesnt work because v cannot be initialized)

var v;
if(sbar is HScrollBar)
    v = (HScrollBar)sbar;
else if(sbar is VScrollBar)
    v = (VScrollBar)sbar;
v.Value = newValue;

Upvotes: 1

Views: 63

Answers (1)

Selman Gen&#231;
Selman Gen&#231;

Reputation: 101731

If both types are inheriting from Scrollbar class then you just need to perform one cast:

private void moveTheScroll(object sbar, int scrollDiff)
{
    var scrollBar = sbar as ScrollBar;

    if(scrollBar != null)
    {
         int newScrollvalue = scrollBar.Value + scrollDiff;
         // do other works with scrollBar...
    }
}

Upvotes: 1

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