Check Exist

Syntax

Exists(filter);

Arguments

filter	Expression<Func<T, bool>>	Criteria by which the records of the repository should be filtered. This parameter must not be empty.	null

Description

Checks if repository contains any record that fulfills the criteria specified in the parameter filter. If there is at least one record that fulfills the criteria, it will return "true", else it will return "false".

Example

Example 1: Counting records by only one criterion

The following program illustrates the function call with only one criterion:

var isExist = repo.Exists(x => x.ProductID == "ADAM-800-BTO");

Function will check if repository contains any record that has "ADAM-567-BTO" as Production ID. If there is at least 1 record, then it will store the boolean value "true" into the variable isExist, else it will store the boolean value "false".

Example 2: Filtering records by multiple criteria

The following program illustrates the function call with multiple criteria:

var isExist = repo.Exists(x => x.ProductID == "ADAM-800-BTO"
                            && x.Quantity > 10 
                            && x.IsUrgent == true);

Function will check if repository contains any record that has "ADAM-567-BTO" as Production ID, has a Quantity of more than 10 and is Urgent. If there is at least 1 record that fulfills all the criteria, then it will store the boolean value "true" into the variable isExist, else it will store the boolean value "false".