NullReferenceException in Mysql Command

Question

I'm Using DataGridView to Display my MySQL Table.

Here's my code:

Public Class Form2
    Dim sqlQuery as String
    Dim sqlQuery As String
    Dim sqlCon As MySqlConnection
    Dim sqlCmd As MySqlCommand
    Dim sqlData As MySqlDataReader
    Dim sqlAdapter As MySqlDataAdapter

    Dim bindEmp As BindingSource
    Dim tblEmp As DataTable

Private Sub Form2_Load(sender As Object, e As EventArgs) Handles       MyBase.Load
          Call SQLConn()

          sqlQuery = "SELECT * FROM employee_info"
          sqlCmd = New MySqlCommand(sqlQuery,sqlCon)
          sqlAdapter.SelectCommand = sqlCmd
          sqlAdapter.Fill(tblEmp)
          bindEmp.DataSource = tblEmp
          DGVStaffAccounts.DataSource = bindEmp
          sqlAdapter.Update(tblEmp)
          End Sub

End Class

I want to display the result, but I'm having a "NullReferenceException" at sqlCmd = New MySqlCommand(sqlQuery, sqlCon)

I don't understand why sqlCmd is Null. Any help would be appreciated.

*EDIT

this is the code inside SQLConn()

Private Sub SQLConn()
    sqlCon = New MySqlConnection("host=localhost; user=root; password=; database=rfid")
    Try
        sqlCon.Open()
    Catch ex As Exception
        MessageBox.Show("Cannot Connect to SQL. Exiting Program")
        Me.Close()
    End Try
End Sub

I'm sorry if I didn't include the code inside SQLConn()

It could be sqlCon that's null, too. What does SQLConn() do? — Ken White, Feb 27 '18 at 17:20
@KenWhite oh I forgot, SQLConn() opens the connection to the mysql database. — Skeeed Row, Feb 27 '18 at 17:21
There is no need for most of those form level vars - the command and datareader objects ought to be created, used and disposed as you need them; if you are using a DataAdapter, you dont need a Connection object, and temp strings are just lazy coding. Please read [ask] and take the [tour] — Ňɏssa Pøngjǣrdenlarp, Feb 27 '18 at 17:22
@Plutonix I'm new to this forum, but thank you for the information :) — Skeeed Row, Feb 27 '18 at 17:26
Its not a forum - we dont have discussions, polls, solicit opinions etc - it is a Q&A site. Read [ask] and take the [tour] — Ňɏssa Pøngjǣrdenlarp, Feb 27 '18 at 17:28

score 0 · Answer 1 · answered Feb 27 '18 at 17:20

0

sqlCon variable is not initialized. Initialize it before passing it to sqlCmd.

answered Feb 27 '18 at 17:20

Hasnain Hayder

99
7

NullReferenceException in Mysql Command

1 Answers1