How to: Modify a Screen by Using Code
Visual Studio LightSwitch 2011 enables you to accomplish many screen-related design tasks by using designers and tool windows. However, there are certain tasks that you might want to accomplish by using code. This topic shows you how to accomplish a set of common screen-related design tasks by using the screen object model. For more information about where you can write code in your application, see any of the following topics:
For general guidance about writing code in Visual Studio LightSwitch 2011, see Writing Code in LightSwitch.
Common Tasks
The following list describes some common data-related tasks that you accomplish by using the screen object model.
- Making controls hidden, read-only, or disabled
Making Controls Hidden, Read-Only, or Disabled
You can hide or show controls on a screen by using code. You can also specify whether controls are read-only or disabled.
The following example hides a company name in a data grid if the company name is Coho Winery. This example also makes the control read-only so that viewers cannot modify the company name by typing text into the control.
Private Sub FindControlInList()
Dim index As Integer = 0
For Each cust As Customer In Customers
If cust.CompanyName = "Great Lakes Food Market" Then
With FindControlInCollection("CompanyName", Customers(index))
.IsVisible = False
.IsReadOnly = True
End With
End If
index = index + 1
Next
End Sub
private void FindControlInList()
{
int index = 0;
foreach (Customer cust in this.Customers)
{
if (cust.CompanyName == "Great Lakes Food Market")
{
this.FindControlInCollection("CompanyName",
this.Customers.ElementAt(index)).IsVisible = false;
this.FindControlInCollection("CompanyName",
this.Customers.ElementAt(index)).IsReadOnly = true;
}
index++;
}
}
The following example hides the company name in a details view on the screen if the company name of the selected item is Coho Winery. This example also disables the Delete button so that users cannot delete a customer who works for Coho Winery.
Private Sub Customers_SelectionChanged()
FindControl("Customers_DeleteSelected").IsEnabled = True
If Me.Customers.SelectedItem.CompanyName = "Great Lakes Food Market" Then
FindControl("CompanyName1").IsVisible = False
FindControl("Customers_DeleteSelected").IsEnabled = False
End If
End Sub
partial void Customers_SelectionChanged()
{
this.FindControl("Customers_DeleteSelected").IsEnabled = true;
if (this.Customers.SelectedItem.CompanyName == "Great Lakes Food Market")
{
this.FindControl("CompanyName1").IsVisible = false;
this.FindControl("Customers_DeleteSelected").IsEnabled = false;
}
}
See Also
Tasks
Concepts
Performing Data-Related Tasks by Using Code