How to Implement a SQL CASE Statement in LINQ using C#?

LINQ CASE Statement Implementation for Complex Conditions

A CASE statement is a powerful tool for evaluating multiple conditions and returning specific results based on each case. This article aims to provide a clear explanation and solution to implementing CASE statements in LINQ for C#.

In one specific scenario, a query seeks to update stock status based on a set of conditions:

osc_products.products_quantity =
      CASE 
         WHEN itempromoflag <> 'N' THEN 100000
         WHEN itemcat1 IN ('1','2','31') AND itemsalestatus = 'S' THEN 100000
         WHEN itemsalestatus = 'O' THEN 0
         ELSE cds_oeinvitem.itemqtyonhand - cds_oeinvitem.itemqtycommitted 
      END 

To translate this CASE statement to LINQ, we can employ the following syntax:

query.Select(item => item.Products_Quantity = 
  item.ItemPromoFlag != 'N' ? 100000 : 
  (item.ItemCat1 == "1" || item.ItemCat1 == "2" || item.ItemCat1 == "31") && item.ItemSaleStatus == "S" ? 100000 : 
  item.ItemSaleStatus == "O" ? 0 : 
  cds_oeinvitem.ItemQtyOnHand - cds_oeinvitem.ItemQtyCommitted);

This LINQ expression uses ternary operators to emulate the CASE statement's conditions and set the corresponding values to the Products_Quantity property. The result is a query that updates the stock status based on the specified conditions.

Note that the provided code snippet assumes that you have already established a LINQ query using an appropriate data source. The query variable in the code should represent the LINQ query you have created.

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