Lambda not working on array
I have the following array
Dim items() = {
New CheckedListBoxItem("NYC", False),
New CheckedListBoxItem("CHI", False),
New CheckedListBoxItem("PHL", False),
New CheckedListBoxItem("SFO", False),
}
I am trying to query against it like this
Try
Dim item As CheckedListBoxI开发者_如何学Pythontem = items.ToList().Where(Function(x) x.Value = "PHL")
MsgBox(item.Value)
Catch ex As Exception
MsgBox(ex.Message)
End Try
I am getting the error
Value cannot be null.
Parameter name: source
I also tried
Dim item As CheckedListBoxItem = items.FirstOrDefault(Function(x) x.Value.ToString() = "PHL")
What am i missing. I just need to query against the list to get an item and change it's checkedstate from false to true.
You need to do:
item = items.ToList().Where(Function(x) x.Value = "PHL").First
MsgBox(item.Value)
First
returns the First item from the collection or throws an exception if the collection is empty.
FirstOrDefault
returns the First item from the collection or the default instance for the type if the collection is empty.
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