TryParse and ConvertToDouble not working on windows tablet with combobox

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C#

I have a piece of code that works fine on a windows laptop/desktop

but when running on tablet I get the error: string not in the correct format with Convert.ToDouble().

code is:

double parseOut = 0;
               double.TryParse(this.comboBox1.Text, out parseOut);


               if (parseOut > 0)
               {
                   Double a = Convert.ToDouble(this.comboBox1.Text);
                   Double b = parseOut;

               }

the combobox holds values, examples:

0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
.........
the user cannot manually enter in the value. combobox.DropDownStlye set to DropDown.

As mentioned when running on PC it works fine but gives error on windows tablet.