"? :" in ASP.NET Core - C#

If you have been working with ASP.NET Core and C#, you have most likely come across the ? : operator. This operator is known as the ternary operator and is a shorthand way of writing an if-else statement. In this article, we will go over some examples of how to use the ? : operator in ASP.NET Core and C#.

Syntax

The syntax of the ? : operator is as follows:

condition ? trueValue : falseValue

Where:

• condition is the condition to check.
• trueValue is the value to return if condition is true.
• falseValue is the value to return if condition is false.

The trueValue and falseValue can be any data type, including objects, strings, and integers.

Examples

Example 1: Checking for Null

One common use case for the ? : operator in ASP.NET Core is to check for null values. For example, suppose you have a nullable integer variable myNumber that might be null. You want to assign a default value of 0 if myNumber is null. You can do this as follows:

int defaultValue = 0;
int result = myNumber ?? defaultValue;

Here, the ?? operator is the null-coalescing operator, which returns the left-hand operand if it is not null, or the right-hand operand otherwise. In this case, myNumber is the left-hand operand, and defaultValue is the right-hand operand.

This is equivalent to the following code using the ? : operator:

int result = myNumber.HasValue ? myNumber.Value : defaultValue;

Here, we are checking if myNumber has a value using the HasValue property. If it does, we return the value using the Value property. If it does not, we return defaultValue.

Example 2: Returning Different Values

Another common use case for the ? : operator in ASP.NET Core is to return different values based on a condition. For example, suppose you have a boolean variable isMale that indicates whether a person is male or not. You want to display different text based on this value. You can do this as follows:

string text = isMale ? "He is male." : "She is female.";

Here, if isMale is true, the value of text will be "He is male.". If isMale is false, the value of text will be "She is female.".

Example 3: Evaluation of Expressions

The ? : operator can also be used to evaluate expressions. For example, suppose you have two integer variables a and b, and you want to determine which one is greater. You can do this as follows:

int max = (a > b) ? a : b;

Here, we are evaluating the expression (a > b) and returning a if it is true, or b otherwise.

Conclusion

The ? : operator is a useful shorthand for if-else statements in ASP.NET Core and C#. It can be used to check for null values, return different values based on conditions, and evaluate expressions. By using the ? : operator, you can write more concise and readable code.