How to make - if no result, result = 0 C#

Question

Let's say i have a textbox and a button, how can i make that button convert the no result (or nothing entered in textbox) to result 0?

    private void button1_Click(object sender, EventArgs e)
    {
        if (this.dateTimePicker1.Text != "")
        {
            listBox1.Items.Add(this.dateTimePicker1.Text);
        }
        textBox2.Text += " Woman";
        if (this.textBox2.Text != "")
        {
            listBox1.Items.Add(this.textBox2.Text);
        }
        textBox3.Text += " People";
        if (this.textBox3.Text != "")
        {
            listBox1.Items.Add(this.textBox3.Text);
        }
    }

If there's nothing entered in textBox2 or textBox3 it converts the result to " Woman" or " People", but i want it to be "0 Woman" & "0 People" - IF NOTHING is entered in textbox. Can anyone help me out?

Answer 1

This is the thing I would do with DRY (Don't repeat yourself)

// Make a list of textboxes and string
List<Tuple<TextBox, String>> textBoxesTest = new List<Tuple<TextBox, String>>();

// Add the information
textBoxesTest.Add(new Tuple<TextBox, String>(textBox2, "Woman"));
textBoxesTest.Add(new Tuple<TextBox, String>(textBox3, "People"));

// Go through the list
foreach(var tuple in textBoxesTest) {
   // tuple.Item1 is a TextBox
   // tuple.Item2 is a String 

   if(String.IsNullOrEmpty(tuple.Item1.Text)) {
      tuple.Item1.Text = String.Format("0 {0}", tuple.Item2);
   } // if end
   else { /* do some other with it */ }
} // foreach end

Don't test string for emptyness with str == "" . Use the String.IsNullOrEmpty(str) method to check this condition. It is faster, because str == "" will create a new String reference to "". Is null or Empty has the condition value == null || value.Length == 0; value == null || value.Length == 0; which will not create instances of a string.

Also make no use of String concatenations, because each will be written in the RAM and then needs to concatenate each time it is used. Better make the use of the String.Format(str, args[]) method.

The above code is well in the issue of maintainability. You just need to add a tuple to the list when adding another textbox "doing the same", and not add if/else algorithm by copy/paste the code. This would be an common error source.

Answer 2

Add following just before last line of function, in order to make nothing into textBox

 textBox2.Text = "";
 textBox3.Text = "";

Answer 3

Add an if-else to check if the textbox text is null and then change the text outrightly rather than appending text to the existing text. Like this

 if (textBox2.Text == "" && textBox3.Text == "")
 {
     textBox2.Text = "0";
     textBox3.Text = "0";
 }

Answer 4

You are very close! Test the contents of textBox2 and textBox3, before appending extra text to it:

if (textBox2.Text == "")
{
  textBox2.Text = "0";
}
textBox2.Text += " Woman";

Answer 5

There are two possibilities to this situation.

1. To handle this on the text-box ( front-end ) side by making sure that an empty string does not get past. If user does not enter anything in the text box, then 0 should be set like a default value or placeholder for that text box. So if user doesn't enter anything, the default value ( in this case 0 ) will still be passed.
2. The other option is to handle it on the handler function. Simply do a check of the value of the textbox that if it is empty, then set it to 0.