Linq to sql updating
In this example, we get a data context to work with first, and then query the Orders table to find a customer with the customer ID of starts with the letter "A", the results are then bound to a Data Grid View control.
The "select new" in the query defines the result type and then sets each of the properties in the type to a value returned by the query.
If the update is true, then the information in the WPF window is to be updated.
Initially, the update was set when the information was passed to the window to get the information inthe fields.
This section will discuss some of the common techniques used in LINQ to SQL statement construction.
In a nutshell, LINQ to SQL provides the developer with the means to conduct queries against a relational database through a LINQ to SQL database model and related data context.
In this case, the query includes a where clause that only returns matches were the customer ID begins is equal to "RICAR": The preceding examples were intended to provide a simple overview as to how to conduct some basic queries against collections using LINQ to SQL and LINQ to Objects; there are certainly a great number of more complex operations that can be executed using similar procedures (groups and aggregation, joins, and so on) however the examples provided are representative of some of the more common types of queries.
There is a single solution included with this download, the solution contains a Windows Forms project called "L2S_Northwind"; this project contains one form (the main form used to display the results of the demonstration queries (frm Main) , and LINQ to SQL database model (North Wind Data Classes.dbml) along with the models designer code and layout file, and a class entitled, "Accessor" that contains code used to perform the LINQ to SQL queries used in the demonstration.
There is a great deal more that one can do with LINQ to SQL that is not contained in this demonstration however, the demonstration was geared towards the mechanics of performing the most typical types of queries that might be required within a data driven application.With this in mind, the single button will need to have a condition to understand if the record is new, or if it exists.I use an Update boolean variable to tell me if the information on the WPF window is to update, or to add.At the end of the query, the output is converted to a List of the Customer Order Result type.In this example, a typed list is created (as in the previous example) using LINQ to SQL, populated, and then the returned typed list is queried using LINQ to Objects.