SQL LINQ Query: Selecting specific column - sql

Question

Today I am needing to write LINQ queries in VB.net to a database table, but am new to SQL/LINQ. This function below is meant to fill a list of strings with all of the possible "Questions" in the database table that match the QuestionType.
However, I only want to select one single column, the QuestionText column, and not all of the data, whenever I have a match.
Public Shared Function RetrieveQuestions(ByVal QuestionType) As List(Of String)
Dim db As New DBDataContext()
db.CommandTimeout = 300
Dim ListOfQuestions As List(Of String) = New List(Of String)
While True
Dim questionList As List(Of Question) = db.Questions.ToList
Dim question As List(Of String) = (From q As Question In questionList Where q.FormType = QuestionType Select q.QuestionText).ToList
Dim i As List(Of String) = question
If (question IsNot Nothing) Then
ListOfQuestions(ListOfQuestions.Count) = i.QuestionText //ERROR
Else
Exit While
End If
End While
Return ListOfQuestions
End Function
In the function above i am encountering an error when trying to update my list with the new QuestionText. "QuestionText is not a member of System.Collections.Generic.List(Of String)". QuestionText is defined as a varchar in my SQL database, so I know that it is definitely a string. I am not trying to set QuestionText to a list of strings, but rather add it to the end of a list of strings.

Answer 1

Direct answer: you'd need to put the whole If (question IsNot Nothing) Then block in a loop like For Each. As the compiler correctly informs - the i variable holds the whole list, not one of its items. Perhaps you forgot you left the LINQ query?
A better solution: I believe you could just use AndAlso q.QuestionText IsNot Nothing - it spares you the need to allocate a new list and to fill it one by one - the following code should do the trick.
Public Shared Function RetrieveQuestions(ByVal QuestionType) As List(Of String)
Dim db As New DBDataContext()
db.CommandTimeout = 300
Dim ListOfQuestions As List(Of String) = (
From q As Question In db.Questions.ToList
Where
q.FormType = QuestionType
AndAlso q.QuestionText IsNot Nothing
Select q.QuestionText
).ToList
Return ListOfQuestions
End Function