检查多个变量C＃的相等性是否相等

Question

Is there a shorthand version of this comparison statement:

if (txtId.Text != string.Empty && txtName.Text != string.Empty && txtBOD.Text != string.Empty && txtPhone.Text != string.Empty)
{//do something }

Is there something like: if all these textboxs values != string.Empty, then do something

Answer 1

You could put the textboxes in an array and use linq like that:

TextBox[] boxes = new [] {txtId, txtName, txtBOD, txtPhone};
if (boxes.All(b => !string.IsNullOrEmpty(b.Text)))
    // do something

You should store the array in a member variable of your window so you don't have to create it again for every check.

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Or (as Habib pointed out) if all those textboxes are in one container control and they are the only textboxes on that control you could use this:

if (containingControl.Controls.OfType<TextBox>().All(b => !string.IsNullOrEmpty(b.Text)))
    // do something

OfType<>() returns a enumeration of all controls in the containingControl 's control collection that are of type TextBox and you can then simply iterate through this sequence with All .

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Note (as others pointed out) that it's a better practice to use string.IsNullOrEmpty() than comparing against string.Empty (since a null check is already included, though that should not matter at a textbox).

Answer 2

You could create a method like this:

private bool AreAllEmpty(params TextBox[] toCheck)
{
    foreach (var tb in toCheck)
    {
        if (!string.IsNullOrEmpty(tb.Text)) return false;
    }

    return true;
}

Or this way with LINQ:

private bool AreAllEmpty(params TextBox[] toCheck)
{
    return toCheck.All(tb => string.IsNullOrEmpty(tb.Text));
}

And then just pass it your collection of text boxes, eg like this:

if(AreAllEmpty(textBox1, textBox2, textBox3, textBox4))
{
    // do something../
}

This approach is good if you're like me and like to reduce method size by off-loading separate operations into their own methods. (This has many advantages: DRY, separation of concerns, etc.)