1.2 KiB
1.2 KiB
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Exceptions |
Exceptions
An exception is an unexpected error that occurs while a program is running, such as an attempt to access a file that does not exist. It will stop the program if not handled.
Example
If we try to read the text of a file that does not exist:
using System.IO;
string content = File.ReadAllText(@"C:\DoesNotExist.txt");
A FileNotFoundException
will be raised.
Some other common exceptions:
IndexOutofRangeException
: Attempted to access an array with an invalid index.NullReferenceException
: Attempted to use an unassigned reference variable.DivideByZeroException
: Attempted to divide by 0.
Best Practices
Use try/catch/finally Blocks
try
{
var client = new WebClient();
var resultData = client.DownloadString("http://github.com");
}
catch (Exception ex)
{
//code for handling exceptions
}
finally
{
//this code is always executed, does not matter if an exception is thrown or not
}
Handle Possible Exceptions With Conditions
Instead of
try
{
conn.Close();
}
catch (Exception ex)
{
//code for handling exceptions.
}
Try this
if (conn.State != ConnectionState.Closed)
{
conn.Close();
}