Understanding the Let Keyword
The Visual Basic syntax offers a keyword named Let that can be used for defining temporary identifiers within query expressions. The following code shows how you can query Windows Forms controls to get a sequence of text boxes:
Dim query = From ctrl In Me.Controls _ Where TypeOf (ctrl) Is TextBox _ Let txtBox = DirectCast(ctrl, TextBox) _ Select txtBox.Name
The Let keyword enables the defining of a temporary identifier so that you can perform multiple operations on each item of the sequence and then invoke the item by its temporary identifier.
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