C# - string.IsNullOrEmpty 不适用于特定文本框

Question

I'm just learning to program and I'm trying to create a program to calculate weight & balance for an aircraft. When you first load this form, I want all the textboxes specified to have a value of 0. I'm running into an issue where one of the boxes is remaining blank and not inputting 0 (Bag Weight). Maybe its something very simple I'm missing? Please see below code:

tb1legBW.text = This is the bag weight I'm referring too.

// This is setting the textbox values to 0 if they are blank. 
        if (string.IsNullOrEmpty(tb1LegOEW.Text) || string.IsNullOrEmpty(tb1LegPW.Text) || string.IsNullOrEmpty(tb1LegBW.Text) ||
            string.IsNullOrEmpty(tb1LegFW.Text) || string.IsNullOrEmpty(tb1LegFuel.Text) || string.IsNullOrEmpty(tb1LegEquip.Text) ||
            string.IsNullOrEmpty(tb1LegAWI.Text) || string.IsNullOrEmpty(tb1LegFB.Text) || string.IsNullOrEmpty(tb1LegCont.Text) ||
            string.IsNullOrEmpty(tb1LegMTOW.Text) || string.IsNullOrEmpty(tb1LegGW.Text) || string.IsNullOrEmpty(tb1LegGD.Text) ||
            string.IsNullOrEmpty(tb1LegMLW.Text) || string.IsNullOrEmpty(tb1LegLW.Text) || string.IsNullOrEmpty(tb1LegLGD.Text))

        {
            tb1LegOEW.Text = "0";
            tb1LegPW.Text = "0";
            tb1LegBW.Text = "0";
            tb1LegFW.Text = "0";
            tb1LegFuel.Text = "0";
            tb1LegEquip.Text = "0";
            tb1LegAWI.Text = "0";
            tb1LegFB.Text = "0";
            tb1LegCont.Text = "0";
            tb1LegMTOW.Text = "0";
            tb1LegGW.Text = "0";
            tb1LegGD.Text = "0";
            tb1LegMLW.Text = "0";
            tb1LegLW.Text = "0";
            tb1LegLGD.Text = "0";
        }

When I run the program the bag weight textbox is blank, unlike the others. Picture is attached: When Program is ran

If someone could please give me some insight on what is happening?

Answer 1

Use string.IsNullOrWhitespace()