asked on

Cannot implicitly convert type 'string' to 'double'

Hi, I'm new to c# and am trying to convert the following code:
Thanks!

private void Sum()
{
double Price1 = 0;
double Price2 = 0;

if (txtItemPrice1.Text == "")
{
Price1 = 0.0;
}
else
{
Price1 = txtItemPrice1.Text; <----
}

if (txtItemPrice2.Text == "")
{
Price2 = 0.0;
}
else
{
Price2 = txtItemPrice2.Text; <---
}

Error Cannot implicitly convert type 'string' to 'double'

if (IsNumeric(txtTax.Text) == false) <----
{
txtTax.Text = 0.0;
}
else if (txtTax.Text == "")
{
txtTax.Text = 0.0;
}

TotalAmt = FormatNumber(Price1 + Price2 + txtTax.Text);
txtItemPriceAmt.Text = FormatNumber(TotalAmt, 2);

Error The name 'IsNumeric' does not exist in the current context

crysallus

conversions in C# are normally done using the Convert class, such as

Price2 = Convert.ToDouble(txtItemPrice2.Text);

Here's the link for all the function's available:

http://msdn.microsoft.com/en-us/library/system.convert%28v=VS.100%29.aspx

To check whether a text string can be converted to a number, use the TryParse methods of one the classes representing the base data type that your number could be in. For example, if you want to test whether the text can be converted to a double, use

if (Double.TryParse(txtTax.Text, out result) == false)
...

http://msdn.microsoft.com/en-us/library/994c0zb1.aspx

SOLUTION

Peter Kwan

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SOLUTION

crysallus

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ASKER CERTIFIED SOLUTION

dougaug

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crysallus

TryParse doesn't throw exceptions, Parse does. If you are going to use Parse as dougang suggested, you would have to surround those calls with a try-catch block. Using TryParse avoids the need for exception handling.

avi7

ASKER

Thanks!