LINQ to SQL

This topic applies to Windows Workflow Foundation 4 (WF4).

This sample demonstrates how to create an activity to use LINQ to SQL query entities from tables in SQL Server databases.

Note:

The WCF samples may already be installed on your machine. Check for the following (default) directory before continuing. <InstallDrive>:\Samples\WCFWFCardspace If this directory does not exist, click the download sample link at the top of this page. Note that this link downloads and installs all of the WF, WCF, and CardSpace samples. This sample is located in the following directory. <InstallDrive>:\Samples\WCFWFCardSpace\WF\Scenario\ActivityLibrary\Linq\LinqToSql

Activity details for FindInSqlTable

This activity allows users to query entities from tables in a database using LINQ to SQL. Users of the activity can also provide a LINQ predicate in the form of a lambda expression to filter the results. If no predicate is provided, the entire table is returned. The following table details the property and return values for the activity.

Property or Return Value	Description
Collection property	A required property that specifies the source collection.
Predicate property	A required property that specifies the filter for the collection in the form of a lambda expression.
Return Value	The filtered collection.

Code Sample that uses the Custom Activity

The following code example uses the FindInSqlTable custom activity to find all rows in a SQL Server table named Employee where the Role column is equal to SDE.

new FindInSqlTable<Employee> 
{
    ConnectionString = @"Data Source=.\SQLExpress;Initial Catalog=LinqToSqlSample;Integrated Security=True",                        
    Predicate = new LambdaValue<Func<Employee, bool>>(c => new Func<Employee, bool>(emp => emp.Role.Equals("SDE"))),
    Result = new OutArgument<IList<Employee>>(employees)
},

To use this sample

1. Open a command prompt.

2. Navigate to the folder that contains this sample.

3. Run the Setup.cmd command file.

   Note

   The Setup.cmd script attempts to install the sample database in your local machine SQL Server Express. If you want to install it in other SQL server instance, edit Setup.cmd.

   The Setup.cmd script does the following actions.:

   • Creates a database called LinqToSqlSample.

   • Creates a Roles table.

   • Creates an Employees table.

   • Inserts 3 records into the Roles table.

   • Inserts 12 records into the Employees table.

4. Using Visual Studio 2010, open the LinqToSQL.sln solution file.

5. To build the solution, press CTRL+SHIFT+B.

6. To run the solution, press F5.

To uninstall the LinqToSql sample database

1. Open a command prompt.

2. Navigate to the folder that contains this sample.

3. Run the Cleanup.cmd command file.

Note:

The samples may already be installed on your machine. Check for the following (default) directory before continuing. <InstallDrive>:\WF_WCF_Samples If this directory does not exist, go to Windows Communication Foundation (WCF) and Windows Workflow Foundation (WF) Samples for .NET Framework 4 to download all Windows Communication Foundation (WCF) and WF samples. This sample is located in the following directory. <InstallDrive>:\WF_WCF_Samples\WF\Scenario\ActivityLibrary\Liiinq\LinqToSql

See Also

Other Resources

LINQ to SQL
Getting Started (LINQ to SQL)