[RESOLVED] [2005] Checking for NULL Values upoon SQL Statment Call

Hello community...

I have a VB.net app that makes a sql call filling in a form.

I want to handle null values but i keep getting errors.

here is the block of code.

Code:

---

    Private Sub searchItem()
        Dim serialSelect As String = "equipment_serial_number"
        Dim cfSelect As String = "equipment_cf_tag"
        Dim sqlRowSelect As String = ""
        Dim searchCriteria As String = ""

        Dim classValue As String = CStr(cboClass.SelectedValue)
        Dim num As Integer = 1

   

        If cboCriteria.SelectedIndex = 0 Then
            sqlRowSelect = serialSelect
        Else
            sqlRowSelect = cfSelect
        End If
        searchCriteria = txtCriteriaValue.Text.ToUpper

        Dim mySqlConnection As SqlConnection = New SqlConnection(getConnectionString)
        Dim mySqlCommand As SqlCommand = New SqlCommand
        Dim mySqlReader As SqlDataReader = Nothing

        mySqlConnection.Open()
        mySqlCommand.Connection = mySqlConnection
        mySqlCommand.CommandText = ( _
        "SELECT equipment_serial_number, equipment_cf_tag, equipment_description, equipment_warranty, item_class_id, location_room_id, status_id, user_id " & _
        "FROM EQ_Equipment " & _
        "WHERE " & sqlRowSelect & " = '" & searchCriteria & "'")
        '**Read and apply values from DB**
        Try
            mySqlReader = mySqlCommand.ExecuteReader
            If mySqlReader.HasRows Then
                While mySqlReader.Read
                    txtSerialNumber.Text = mySqlReader.GetString(0)


                    txtCfTag.Text = mySqlReader.GetString(1)

 --------------> If IsDBNull(mySqlReader.GetString(2)) Then
                        MessageBox.Show("yes im null")
                    Else
                        'txtNotes.Text = mySqlReader.GetString(2)
                    End If

                    dtpWarranty.Value = mySqlReader.GetDateTime(3)
                    cboClass.SelectedValue = mySqlReader.GetInt32(4)
                    cboLocation.SelectedValue = mySqlReader.GetInt32(5)
                    cboStatus.SelectedValue = mySqlReader.GetInt32(6)
                    cboUserName.SelectedValue = mySqlReader.GetInt32(7)
                    lblBoxDept.Text = getDepartment(mySqlReader.GetInt32(7))
                End While
                previousSerial = txtSerialNumber.Text

                If classValue = num.ToString Then
                    getBigBrother()
                End If

                searchfound()
                variableUpdate()

            Else

                If cboCriteria.SelectedIndex = 0 Then
                    MessageBox.Show("No item found with serial number: " & txtCriteriaValue.Text, "no record", MessageBoxButtons.OK)
                Else
                    MessageBox.Show("No item found with property decal " & txtCriteriaValue.Text, "no record", MessageBoxButtons.OK)
                End If
                clearNonEditContent()
            End If
        Catch ex As Exception
            MessageBox.Show(ex.Message)
        End Try
        mySqlConnection.Close()
    End Sub

---

THE area in bold is what im trying to handle but i suppose if i get it working i can use it for any field. the error im getting is:

"Data is Null. This method or property cannot be called on null values."

So im stumped.. I tested the code with a check to see what it was pulling from the database using getsqlvalue and it says "Null".. so im stuck...

Any help would be appreciated.

The SQL reader has it's own IsDBNull method. Use that instead

Code:

---

    If mySqlReader.IsDBNull(2) Then

    End If

---

DOH!.. thanx...

I actualy used that but i did not put my column refrence "(2)" at the end of the method.

Again thanx...

you can also check a value to see if it equals system.dbnull.value, but the method I already posted is your best bet in this scenario when using a datareader.