C# Tutorials
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C# Access Modifiers
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C# Exceptions
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C# Exceptions
When using C # code, various errors may occur: editorial errors made by the editor, errors due to incorrect input, or other unexpected items.
In the event of an error, C # will usually stop and produce an error message. The technical term for this is: C# will issue an exception (throw an error).
C# try and catch
The try statement allows you to define a block of code to be tested for errors while it is being executed.
The catch statement allows you to define a block of code to be executed, if an error occurs in the try block.
The try and catch keywords come in pairs:
Syntax
try
{
// Block of code to try
}
catch (Exception e)
{
// Block of code to handle errors
}Consider the following example, in which we compiled a list of three whole numbers:
This will generate an error, because myNumbers[10] does not exist.
int[] myNumbers = {1, 2, 3};
Console.WriteLine(myNumbers[10]); // error!In the event of an error, we can use a try ... catch to catch the error and issue a specific code to handle it
In the following example, we use variations within the capture block (e) and the built-in Message structure, which produces a message explaining the difference:
Example
try
{
int[] myNumbers = {1, 2, 3};
Console.WriteLine(myNumbers[10]);
}
catch (Exception e)
{
Console.WriteLine(e.Message);
}You can also extract your error message:
Example
try
{
int[] myNumbers = {1, 2, 3};
Console.WriteLine(myNumbers[10]);
}
catch (Exception e)
{
Console.WriteLine("Something went wrong.");
}Finally
The finally statement allows you to create code, after try...catch, regardless of the result:
Example
try
{
int[] myNumbers = {1, 2, 3};
Console.WriteLine(myNumbers[10]);
}
catch (Exception e)
{
Console.WriteLine("Something went wrong.");
}
finally
{
Console.WriteLine("The 'try catch' is finished.");
}
The throw keyword
Throw Statement allows you to create a custom error.
The throw statement is used with a separate section. There are many different classes available in C #: ArithmeticException, FileNotFoundException, IndexOutOfRangeException, TimeOutException, etc:
Example
static void checkAge(int age)
{
if (age < 18)
{
throw new ArithmeticException("Access denied - You must be at least 18 years old.");
}
else
{
Console.WriteLine("Access granted - You are old enough!");
}
}
static void Main(string[] args)
{
checkAge(15);
}If age was 20 years old, you would not get an exception:
Example
checkAge(20);