[RESOLVED] [02/03]Add values to a hash table

[Chathura]

Hi All,
I'm trying to get data (2 columns) from SQL Server 2000 database (it sounds ok) to a datatable and adding these data to a hashtable for lookup and add one column to a combo box. when an item is selected from the combo box it get to the appropriate referenced value from the hash table. But when I'm going to run it, an error is occurred at the marked area. I'm sure I've done a greate mistake. Please help me to get rid of this.

Private Sub PopulateCustomer()
        '//This procedure retriews all customers
        Dim SelectProducts = New SqlClient.SqlCommand
        Dim myReader As SqlDataReader
        MyConnection = New SqlConnection(MyCONNECTIONSTRING)
        SelectProducts = New SqlClient.SqlCommand("SELECT Name, DCLink FROM Client Order By Name", MyConnection)
        MyConnection.Open()
        myReader = SelectProducts.ExecuteReader()
        myDataColumn = New DataColumn
        myDataColumn.DataType = System.Type.GetType("System.Int16")
        myDataColumn.ColumnName = "id"
        myDataColumn.ReadOnly = True
        myDataColumn.Unique = True
        tblCustomer.Columns.Add(myDataColumn)
        '==>>>
        myDataColumn = New DataColumn
        myDataColumn.DataType = System.Type.GetType("System.String")
        myDataColumn.ColumnName = "CustomerName"
        myDataColumn.AutoIncrement = False
        myDataColumn.Caption = "Customer Name"
        myDataColumn.ReadOnly = False
        myDataColumn.Unique = False
        tblCustomer.Columns.Add(myDataColumn)
 
        If myReader.HasRows Then
            Do While myReader.Read()
                myDataRow = tblCustomer.NewRow()
                myDataRow("id") = myReader.GetValue(1)
                myDataRow("CustomerName") = myReader.GetString(0)
                tblCustomer.Rows.Add(myDataRow)
            Loop
        Else
            MsgBox("Customer Database is empty", MsgBoxStyle.Information + MsgBoxStyle.OKOnly, "Load Customer")
        End If
        MyConnection.Close()
        MyConnection = Nothing
        myReader = Nothing
        Dim Lookup As New Hashtable
<'--This is the area the error is occurred
       [COLOR=DarkOrange] For Each Row As DataRow In tblCustomer.Rows  
            Lookup.Add("id", "CustomerName")
            cboCustomer.Items.Add("CustomerName")
        Next[/COLOR]
  '--This is the area, the error is occurred>
    End Sub

[jmcilhinney]

You don't need the Hashtable at all. Just use a DataAdapter to populate your DataTable directly. That way you don't have to worry about building the schema, reading the query results one record at a time or adding the records to the table. That whole block of code reduces to a few lines:

Dim dt As New DataTable
Dim da As New SqlDataAdapter("query here", myConnection)
 
da.Fill(dt)
cboCustomer.DisplayMember = "Name"
cboCustomer.ValueMember = "DCLink"
cboCustomer.DataSource = dt

That's it. When the user selects a Name value from the list you get the corresponding DCLink value from the ComboBox's SelectedValue property.

Also, can I recommend some consistency in your naming conventions? You're using Hungarian notation in some places, e.g. tbl and cbo, but not others, plus you're starting some variable names with lower case letters and others with upper case. Consistency is very important when writing code or it simply gets confusing. I strongly suggest that you chooses Hungarian notation or not and camel or Pascal casing and stick to it. The .NET convention is to NOT use Hungarian notation at all and to use camel casing (first letter lower case) for variables and Pascal casing (first letter upper case) for just about everything else. Unless you have a valid reason for doing otherwise I suggest that you choose that and stick to it.

[Chathura]

You don't need the Hashtable at all. Just use a DataAdapter to populate your DataTable directly.

You are correct but what I want is to try with a Hashtable example. Any way, Thank you very much for coming my help.

Also, can I recommend some consistency in your naming conventions? You're using Hungarian notation in some places, e.g. tbl and cbo, but not others, plus you're starting some variable names with lower case letters and others with upper case. Consistency is very important when writing code or it simply gets confusing. I strongly suggest that you chooses Hungarian notation or not and camel or Pascal casing and stick to it. The .NET convention is to NOT use Hungarian notation at all and to use camel casing (first letter lower case) for variables and Pascal casing (first letter upper case) for just about everything else. Unless you have a valid reason for doing otherwise I suggest that you choose that and stick to it.

Thank you for your suggession and I appreciate it. I'm sorry to put a code with various notations within a single procedure. That was happen just because I was experimenting by putting codes here and there. I'm sorry , and thank you again