Uploading Datagridview data to MySQL DB - mysql

Question

i created a simple mass upload of data from CSV to datagridview and save all datagridview rows into my MySQL table, the code works perfectly but when i check my database it insert a null values to my table heres my code.
This is my Button for Adding all values from my Datagridview
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim cmd As MySqlCommand
connection.Open()
Dim i As Integer
For i = 0 To DataGridView1.Rows.Count - 2
Dim row As DataGridViewRow = DataGridView1.Rows(i)
cmd = New MySqlCommand("INSERT INTO tbl_handling(tbl_docnumber,tbl_bpref,tbl_cname) values (#docnumber,#bref,#cname)", connection)
cmd.Parameters.Add("#docnumber", MySqlDbType.Int64).Value = DataGridView1.Rows(i).Cells(0).Value.ToString
cmd.Parameters.Add("#bref", MySqlDbType.VarChar).Value = DataGridView1.Rows(i).Cells(1).Value.ToString
cmd.Parameters.Add("#cname", MySqlDbType.VarChar).Value = DataGridView1.Rows(i).Cells(2).Value.ToString
cmd.ExecuteNonQuery()
Next
connection.Close()
connection.Dispose()
MessageBox.Show("Data All Uploaded")
End Sub
This is my code on inserting CSV file to my Datagrid view
Private Sub btnUpload_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSelectData.Click
Dim fName As String = ""
OpenFileDialog1.InitialDirectory = "D:\TestFile"
OpenFileDialog1.Filter = "CSV files(*.csv)|*.csv"
OpenFileDialog1.RestoreDirectory = True
Dim colespected As Integer = 5
Dim sline As String = ""
If (OpenFileDialog1.ShowDialog() = Windows.Forms.DialogResult.OK) Then
fName = OpenFileDialog1.FileName
Dim thereader As New StreamReader(fName, Encoding.Default)
Do
sline = thereader.ReadLine
If sline Is Nothing Then Exit Do
Dim words() As String = sline.Split(",")
DataGridView1.Rows.Add("")
For ix As Integer = 0 To 2
DataGridView1.Rows(DataGridView1.Rows.Count - 1).Cells(ix).Value = words(ix)
Next
Loop
thereader.Close()
End If
End Sub

Answer 1

I am assuming that your data is displaying successfully in the grid. So I am only addressing the Button event.
Both commands and connections need to be closed and disposed. Using...End Using blocks do this for you. (BTW Stream objects should be in Using blocks also.) Database objects should be local to the method where they are used. If you .Dispose a connection how do you expect to .Open it later? The command and parameters collection are only created once outside the loop. Just the .Value changes inside the loop.
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Using connection As New MySqlConnection(ConStr),
cmd As New MySqlCommand("INSERT INTO tbl_handling(tbl_docnumber,tbl_bpref,tbl_cname) values (#docnumber,#bref,#cname)", connection)
cmd.Parameters.Add("#docnumber", MySqlDbType.Int64)
cmd.Parameters.Add("#bref", MySqlDbType.VarChar)
cmd.Parameters.Add("#cname", MySqlDbType.VarChar)
connection.Open()
For i = 0 To DataGridView1.Rows.Count - 2
cmd.Parameters("#docnumber").Value = CLng(DataGridView1.Rows(i).Cells(0).Value)
cmd.Parameters("#bref").Value = DataGridView1.Rows(i).Cells(1).Value.ToString
cmd.Parameters("#cname").Value = DataGridView1.Rows(i).Cells(2).Value.ToString
cmd.ExecuteNonQuery()
Next
End Using
MessageBox.Show("Data All Uploaded")
End Sub
I am a bit worried that tbl_docnumber is an auto-number (identity) primary key in the database. If this is so, then this field should be omitted from the Insert.
This operation would be easier if you filled a DataTable instead of a DataGridView. You could then use a DataAdapter to update the database.