Beginning C# 7 Hands-On - The Core Language

Working with the Convert class

Beneath comment 12, you'll add the following line:

double value = Convert.ToDouble(TextBox1.Text);

Notice the class called Convert. If you hover your mouse over Convert, it says Converts a base data type to another base data type. So, basically this is a nice class: a collection of functionality that we can use to convert between different data types.

Now, in our particular case, we say Convert.ToDouble, and specifically we'll take the input from the box; so we finish with TextBox1.Text.

Remember that this line will read from the TextBox control, and the value will be converted to a double data type and then saved over to the variable named value. So, all of that will happen within that single line.