Function to return a List for a dropdownlist or combobox

Question

User-585544258 posted

 Hi everbody.  I'm new to programming, and have only done a few things.  I have written a function before to delete and update records, but never anything to return values back to my call of the function.  Here is my code, and I will try to explain what I'm trying to acheive.

        If Not Att1 = "" Then
            Attribute1.Text = Att1
            Attribute1.Visible = True
            ComboBox1.Visible = True
            Dim Conn1 As New SqlConnection(ConfigurationManager.ConnectionStrings("ReportingConnectionString").ToString())
            Dim Cmd1 As New SqlCommand("SELECT Distinct Attribute FROM Attributes Where AttributeName = @String1", Conn1)
            Dim String1 As SqlParameter = Cmd1.Parameters.Add("@String1", Data.SqlDbType.VarChar, 48)
            String1.Value = Att1
            Cmd1.CommandType = CommandType.Text
            Cmd1.Connection.Open()
            Dim ddlValues1 As SqlDataReader
            ddlValues1 = Cmd1.ExecuteReader()
            ComboBox1.DataSource = ddlValues1
            ComboBox1.DataValueField = "Attribute"
            ComboBox1.DataTextField = "Attribute"
            ComboBox1.DataBind()
            Cmd1.Connection.Close()
            Cmd1.Connection.Dispose()
            ComboBox1.SelectedValue = "Select Value...."
        End If

        If Not Att2 = "" Then
            Attribute2.Text = Att2
            Attribute2.Visible = True
            ComboBox2.Visible = True
            Dim Conn2 As New SqlConnection(ConfigurationManager.ConnectionStrings("ReportingConnectionString").ToString())
            Dim Cmd2 As New SqlCommand("SELECT Distinct Attribute FROM Attributes Where AttributeName = @String2", Conn2)
            Dim String2 As SqlParameter = Cmd2.Parameters.Add("@String2", Data.SqlDbType.VarChar, 48)
            String2.Value = Att2
            Cmd2.CommandType = CommandType.Text
            Cmd2.Connection.Open()
            Dim ddlValues2 As SqlDataReader
            ddlValues2 = Cmd2.ExecuteReader()
            ComboBox2.DataSource = ddlValues2
            ComboBox2.DataValueField = "Attribute"
            ComboBox2.DataTextField = "Attribute"
            ComboBox2.DataBind()
            Cmd2.Connection.Close()
            Cmd2.Connection.Dispose()
            ComboBox2.SelectedValue = "Select Value...."
        End If

That codes goes on up to att20.  It works just fine, but it is forever long, and I would like to clean it up.

I want to do something like:

comboboxfill(Att1)

Or, should I pass the combobox number also, so that the code can fill the appropriate combobox?  Like.

comboboxfill(Att1,Combobox1)

Any help on how to write the function and how to pass back the information or just how to make it work in general would be apprecitated.

Thanks in advance for your help.

Answer 1

User-1112770754 posted

Yes, call a function and pass the Combobox to fill and the "attributename".  Then use the same connection string... command object, sqlParameter object etc.

I've not tested the below ... but, it should get you in the right direction.

If this helps, pls mark as "Answer".

thanks.

 public static void LoadCombo(cboToFill as ComboBox, strAttrib as String)
        {
   Dim Cmd2 As New SqlCommand("SELECT Distinct Attribute FROM Attributes Where AttributeName = @String2", Conn2)  
   Dim String2 As SqlParameter = Cmd2.Parameters.Add("@String2", Data.SqlDbType.VarChar, 48)  
   String2.Value = strAttrib  
   Cmd2.CommandType = CommandType.Text  
   Cmd2.Connection.Open()  
   Dim ddlValues2 As SqlDataReader  
   ddlValues2 = Cmd2.ExecuteReader()
           
   Dim Conn As New SqlConnection(ConfigurationManager.ConnectionStrings("ReportingConnectionString").ToString()) 
   cboToFill.DataSource = ddlValues2  
   cboToFill.DataValueField = "Attribute" 
   cboToFill.DataTextField = "Attribute" 
   cboToFill.DataBind()
  
        }

Answer 2

User-585544258 posted

 I think your code will work, but when I put in cbotofill as ComboBox it underlines it in blue and says type combobox is not defined.  If i change it to cbotofill as Dropdownlist it understands it.  Any ideas on how to get combobox defined?  Or do I just call cbotofill as an object?

Answer 3

User1383809551 posted

Hi,

There is nothin called ComboBox here.. you can use DropDown itself it is equalant to combobox

Thanks

Answer 4

User-585544258 posted

 That doesn't seem to work.  It says Value of type 'Ajaxcontroltoolkit.combobox' cannot be converted to 'System.Web.UI.Webcontrols.Dropdownlist'.

Answer 5

User-1112770754 posted

a quick fix should be...

public static void LoadCombo(cboToFill as System.Web.UI.Webcontrols.Dropdownlist, strAttrib as String)

etc.

 

 

 

Answer 6

User-585544258 posted

 This seemed to work as an object: 

    Public Function fillcombobox(ByVal cbotofill As Object, ByVal Att As String) As Object
        Dim Conn1 As New SqlConnection(ConfigurationManager.ConnectionStrings("ReportingConnectionString").ToString())
        Dim Cmd1 As New SqlCommand("SELECT Distinct Attribute FROM Attributes Where AttributeName = @String1", Conn1)
        Dim String1 As SqlParameter = Cmd1.Parameters.Add("@String1", Data.SqlDbType.VarChar, 48)
        String1.Value = Att
        Cmd1.CommandType = CommandType.Text
        Cmd1.Connection.Open()
        Dim ddlValues1 As SqlDataReader
        ddlValues1 = Cmd1.ExecuteReader()
        cbotofill.DataSource = ddlValues1
        cbotofill.DataValueField = "Attribute"
        cbotofill.DataTextField = "Attribute"
        cbotofill.DataBind()
        Cmd1.Connection.Close()
        Cmd1.Connection.Dispose()
        cbotofill.SelectedValue = "Select Value...."

End Function

Then Call it by:

fillcombobox(ComboBox1, Att1)

Thank you very much for your help.