Which is best for performance

Can anyone shed some light on this for me. Which would be better for performance

    foreach (DataRow row in prodStockLevels.Rows)
    {
     开发者_开发技巧  string stock = row["stpt_Stock"].ToString();
       textbox.text = stock;
    }

or

    foreach (DataRow row in prodStockLevels.Rows)
    {
       textbox.text = row["stpt_Stock"].ToString();
    }

Would there be much difference even if the datatable is huge. Just want to know is it better for performance if the data is passed directly.

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There'll be no discernable difference in efficiency - I doubt that it's even measurable, if it exists at all.

The fact that you're assigning to a local variable will basically be irrelevant. The value of the expression row["stpt_Stock"].ToString() will end up on the stack either way. The only difference is whether that stack slot has a name or not.

In the debugger it might make a tiny but just-about measurable difference as it may have some additional implications - but certainly not enough to worry about.

I think I'd be more worried about the fact that you're repeatedly assigning values to the same textBox.Text property - only the last one is actually going to be relevant. You'd be better off just fetching the last row...

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No difference. Probably the exact same code after compilation.

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No difference.
The following will be faster than both:

 textbox.text = prodStockLevels.Rows.Last()["stpt_Stock"].ToString();