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Preprocess Query In Lightswitch 2011

Software Requirement

1. Visual studio 2010 is installed on your machine.
2. Visual Studio 2010 service pack 1 is installed on your machine.
3. Microsoft Visual Studio Light switch 2011 is installed on your machine.

Prerequisite Knowledge

1. Basics about lightswitch.
2. How to create screens in lightswitch?
3. How to create tables in lightswitch?

What Is Preprocess Query

Scenario

Steps Of Execution

1. Create a new project
2. Add tables
3. Add screen
4. Add data to tables
5. Write preprocess query

Create A New Project

Add Tables

Add Screen

Add Data To Tables

Write Preprocess Query

1. Open Employees table (from Data Sources – ApplicationData)
2. From the ‘Write Code’ option select ‘Employees_All_PreprocessQuery’ as shown in figure below

Click to Enlarge

partial void Employees_All_PreprocessQuery(ref IQueryable < Employee > query) {
  var setting = this.DataWorkspace.ApplicationData.SortSettingsSet.FirstOrDefault();
  if (setting != null) {
    if (setting.SortFieldName.CompareTo("NAME") == 0) {
      query = query.OrderBy(x => x.EmployeeName);
    } else if (setting.SortFieldName.CompareTo("DOJ") == 0) {
      query = query.OrderBy(x => x.DOJ);
    }
  }
}

Output