C # Celsius Fahrenheit conversion

Transformation

private void Buttonctof_click (object sender, System.EventArgs e)
{
Double c=0,f;
try//the input error with the thrown exception to replace the regular.
{c=convert.todouble (textBox1.Text.ToString ());} Convert conversion function, easy to use
catch (Exception)
{
Textbox1.clear ();
Label2. text= "Please enter a number!" ";
Label2. Visible=true;
return;//must have returned, otherwise the following code will still be executed
};
f=1.8*c+32;//Celsius formula for conversion to Fahrenheit
Label2. text= "Celsius" +c+ "degree of conversion to Fahrenheit is:" +F;
Label2. Visible=true;
}