Hello,

I can't figure out why it' possible to convert my string. Error message is: input string was not in correct format

This is my code, which make an error:

Dim dbl as Double
Dim str as String = "£22.50")
str = str.Replace("£", "")
str = str.Replace(".", ",")
dbl = Convert.ToDouble(str)

But if I try this, it's work:

dbl = Convert.ToDouble("22,50")

What's going on ?

{

string s = "22.45";
        double p = Convert.ToDouble(s);
        Response.Write(p.ToString());

}

This worked perfectly fine.

 Hi,

Dim dbl As Double
        Dim str As String = "£22.50"
        Str = Str.Replace("£", "")
        Str = Str.Replace(".", ",")
        dbl = Convert.ToDouble(str)
        TextBox1.Text = dbl;

This is working with me

 It also depends of the current culture of the thread executing Convert.ToDouble()

For instance Convert.ToDouble("22,50") works fine if CurrentCulture is French because French use a coma as decimal separator.

You don't necessare need to change the default of the thread's culture; you can define the convesion provider. You don't necessary need to remove the currency symbol either if you provide the proper conversion params. For instance in the snippet below I also assumed you would need to have a space as group separator instead of the american style's coma:

System.Globalization.NumberFormatInfo nfi = new
System.Globalization.NumberFormatInfo();
nfi.CurrencySymbol = "£";
nfi.CurrencyDecimalSeparator = ",";
nfi.NumberGroupSeparator = " ";
nfi.NumberDecimalDigits = 2;
decimal d = Decimal.Parse("£78 022.50", nfi);

Bye

A good idea also is to use TryParse.  That will catch any errors:

double result = 0;
if(double.TryParse(yourstring, out result))
{
      // valid double
}

I tried the code

string ax = "$22.50";
        ax = ax.Replace("$", "");
        ax = ax.Replace(".", ",");
        Response.Write("ax is " + ax);

        double dx = Convert.ToDouble(ax);
        Response.Write("dx is: " +dx.ToString());

and it works fine.

 What culture are u using?

Thank you guys for all your answers. Method TryParse resolved my problem.