Binding data to a DataGridView - vb.net

Question

I have a bit of code which loads data from a stored procedure in MS SQL Server and then loads the data into a DataGridView, which works fine. What I want is for the code that connects / loads the data to sit in my Database class and then everything associated with the DataGridView to be stored in my Form but I am having problems passing the contents of the BindingSource over to the Form from the Database class.
Form1 code:
Public Class Form1
Dim myDatabaseObj As New Class1()
Dim bindingSource1 As New BindingSource()
Dim connectString As New SqlConnection
Dim objDataAdapter As New SqlDataAdapter
Dim table As New DataTable()
Dim tabletest As New DataTable()
Private Sub loadCompanyList()
Try
Me.dgv_CompanyList.DataSource = Me.bindingSource1
getCompanyList()
Catch ex As NullReferenceException
End Try
End Sub
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
loadCompanyList()
End Sub
End Class
When I try place the getCompanyList() in a class and then create a new object that references the Form() it does not seem to return any value from the table to the MyForm.BindingSource1.Datasource meaning my DataGridView displays no data.
Database class code:
.....
Private Sub getCompanyList()
Try
Dim myForm as new Form()
connect_Transaction_Database()
objDataAdapter.SelectCommand = New SqlCommand()
objDataAdapter.SelectCommand.Connection = connectString
objDataAdapter.SelectCommand.CommandText = "sp_GetCompanyList"
objDataAdapter.SelectCommand.CommandType = CommandType.StoredProcedure
Dim commandBuilder As New SqlCommandBuilder(Me.objDataAdapter)
Dim table As New DataTable()
table.Locale = System.Globalization.CultureInfo.InvariantCulture
Me.objDataAdapter.Fill(table)
**MyForm.bindingSource1.DataSource = table**
Catch ex As DataException
MsgBox(ex.Message)
Catch ex As NullReferenceException
MsgBox(ex.Message)
End Try
disconnect_Transaction_Database()
End Sub

Answer 1

This question has just been bumped by the Community user so I thought I would provide an answer which may help others in the future.
Firstly, I would consider implementing Using:
Managed resources are disposed of by the .NET Framework garbage collector (GC) without any extra coding on your part. You do not need a Using block for managed resources. However, you can still use a Using block to force the disposal of a managed resource instead of waiting for the garbage collector.
Secondly, you don't need to use a SqlDataAdapter. Instead you can load a DataTable using the SqlCommand class and return that. I would also contain the SqlConnection in the method rather than having it opened and closed in a different one.
Your code would look something like this:
Form1 code:
Public Class Form1
Private Sub loadCompanyList()
Dim myDatabase As New Database
Me.dgv_CompanyList.DataSource = myDatabase.getCompanyList()
End Sub
End Class
Database code:
Public Class Database
Public Function getCompanyList() As DataTable
Dim dt As New DataTable
Using con As New SqlConnection(connectionString),
cmd As New SqlCommand("sp_GetCompanyList", con) With {.CommandType = CommandType.StoredProcedure}
con.Open()
dt.Load(cmd.ExecuteReader())
End Using
Return dt
End Function
End Class

Answer 2

You want getCompanyList to be a function, which returns a DataTable. Then, forget the BindingSource (if the DataGridView is read-only) and set the DataSource property to the function:
Me.dgv_CompanyList.DataSource = getCompanyList

Answer 3

I would suggest you make the GetCompanyList method into a Function that returns the DataTable filled by the SqlDataAdapter. There's no real reason this Sub should have a dependency on the form. Instead a method in the form could call this to get the DataTable and then perform the binding.
Public Function GetCompanyList() As DataTable
...
...
Dim table As New DataTable()
table.Locale = System.Globalization.CultureInfo.InvariantCulture
Me.objDataAdapter.Fill(table)
Return table
...
...