Check DGV row for missing value with an sql bound back end - vb.net

Question

I am currently working in vb.net windows express 2013 with an sql back end. I am trying to create an if statement that will look at a specific cell and make a decision based on if the cell has nothing in it or not. I think the return for an sql statement is null but im not 100% sure. I have tried lots of codes I dug up on the internet but none of them have worked for me so far. Here is the line:
Dim Row_Index As Integer = DGVStart.CurrentCell.RowIndex
If DGVStart.Rows(Row_Index).Cells(1).Value Is Nothing Then
This code does work, as in the windows express is telling me the line is fine, however, it seems that I am always getting the return of nothing, even if something is in the cell.I think this problem has something to do with the way i am pulling the value. I have a datagridview checkbox column which i manually added in the design form and if i change it to cells(0), which is my manually inserted column, it picks it up every time. I need to know how to tell my program to differentiate between is null and is not null.
UPDATE: I am now running into new issues after changing to searching for dbnull. here is my code.
Private Sub DGVStart_CellContentClick(sender As Object, e As DataGridViewCellEventArgs) Handles DGVStart.CellContentClick
'dim start time
Dim start As String = TxtStart.Text
'fail safe so headers cant be clicked
If e.RowIndex = -1 Then
Exit Sub
End If
'dim row index and check, check is for the parts shear columns
Dim Row_Index As Integer = DGVStart.CurrentCell.RowIndex
'Dim check As String = DGVStart.Rows(Row_Index).Cells(2).Value
'if checkbox is clicked
If e.ColumnIndex = 0 Then
'---------------------------------------------Normal parts---------------------------------------------------------------
'If DGVStart.Rows(Row_Index).Cells(1).Value Then
If IsDBNull(DGVStart.Rows(Row_Index).Cells(3).Value) = True Then
Dim Shear As Date = DGVStart.Rows(Row_Index).Cells(5).Value
Dim Machine As Int16 = DGVStart.Rows(Row_Index).Cells(4).Value
Dim ShearNumber As String = DGVStart.Rows(Row_Index).Cells(1).Value
Dim Parts As String = DGVStart.Rows(Row_Index).Cells(3).Value
'Pull Values for sql statement and other operations
Try
'set up for checkbox event to trigger
If e.ColumnIndex = 0 Then
'safety messagebox
Dim result As Integer = MsgBox("Are you sure Shear Number " & ShearNumber & " is being started?", MessageBoxButtons.YesNo)
'if messagebox is no
If result = DialogResult.No Then
Exit Sub
'if messagebox is yes
ElseIf result = DialogResult.Yes Then
'sql update
Using conn1 As New SqlConnection(connstring)
conn1.Open()
Using comm1 As New SqlCommand("UPDATE table1 SET " & start & " = getdate() Where col = value AND col = value", conn1)
With comm1.Parameters
.AddWithValue("#Shear", Shear)
.AddWithValue("#Machine", Machine)
End With
comm1.ExecuteNonQuery()
End Using
conn1.Close()
End Using
End If
End If
Catch ex As Exception
MsgBox(ex.ToString)
MsgBox("Error checking off start date for this machine, please contact the manufacturing enginnering department.")
End Try
Call refresh()
Call refresh2()
'--------------------------------------------------------Parts special--------------------------------------------------
Else
MsgBox("Parts")
End If
End If
End Sub
***Please note my sql statements have been modified to protect the company I am working for but I am sure the sql code works.
NEW PROBLEM: I am receiving a null error message because if i uncomment this line:
If DGVStart.Rows(Row_Index).Cells(1).Value Then
Then I am trying to see if a cell is null but that causes an error. I am trying to use my if statement to either run the normal parts, or special parts of my code.
Thanks,