Conditional Expression represents an expression that has a conditional operator.
You can use the Expression.Condition factory method to create a ConditionalExpression. For example, you have the following code.
int num = 60;
if(num > 10)
{
Console.WriteLine("num is greater than 10");
}
else
{
Console.WriteLine("num is less than or equan to 10");
}
Here is the code that is required to build the same functionality using expression tree.
int num = 60;
Expression conditionExpr = Expression.Condition(
Expression.Constant(num > 10),
Expression.Constant("num is greater than 10"),
Expression.Constant("num is smaller or equal to 10")
);
// The following statement first creates an expression tree,
// then compiles it and then executes it.
Console.WriteLine(Expression.Lambda<Func<string>>(conditionExpr).Compile()());
The Condition method evaluates the first expression which is the test condition and if it is true, the second expression will be executed otherwise the third expression will be executed.