Question

I have a data reader to read the datas from database.
I am reading TotalPrice from sales table.
I would like to show the total price as 2 decimal place.

The code is something link that:

TotalPrice.Text = myReader["TotalPrice"].ToString("N2");

However i encounted this error: no overload for method “ToString” takes 1 arguments
What’s wrong with the code?

Answer 1

Assuming that TotalPrice is a Decimal column, and that myReader is a DataReader:

TotalPrice.Text = myReader.GetDecimal(myReader.GetOrdinal("TotalPrice")).ToString("N2");

The idea here is that myReader’s indexer (what you are using when you call myReader["TotalPrice"]) returns an Object. It has to, since it doesn’t know at compile time what type the column is. By using .GetDecimal(), you are assuring that you get a Decimal value back, or an error.

The .ToString overload that takes a format string is declared on Decimal, not on Object. Object’s .ToString takes no arguments.

The inner call to GetOrdinal returns the field’s index given the name- if you are doing this in a loop for multiple data rows, you’d probably want to cache that in a variable.