比较C＃中的两个文本框

Question

How can I compare two textboxes in c# using greater than or less than. Im working on billing system. I want the cash shoould be bigger than the total. if not. it will pop up messagebox for error. I already try convert to int. to double. to string. Here's my current code right now.

if (txtCash.TextLength < txtTotal.TextLength){
    MessageBox.Show("Cash must me bigger than the        total");
    txtCash.Focus();
    return;
  }

Any one can help me how? I know text length is wrong. but im just using it.

Answer 1

I'm working on billing system. I want the cash should be bigger than the total. if not. it will pop up message box for error.

You might be looking for something like this:

if (double.Parse(txtCash.TextLength) <= double.Parse(txtTotal.TextLength))
{
    MessageBox.Show("Cash must me bigger than the total");
    txtCash.Focus();
    return; // i dont know why you put this here but i'll leave it there anyway.
}
else
{
    var amount = double.Parse(txtCash.TextLength);
    // DO something
}

You may want to further validate the user input if you wish. Example, if the user doesn't enter numbers...

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Better ways to achieve your task in the most robust way possible, you should consider the below links:

How do I make a textbox that only accepts numbers?

double.TryParse(...)

Update:

Seems, you're not sure about the keyword var . I suggest you have a deep read of the MSDN reference page for var .