CODEWITHSUNDEEP
c#asp.netvb.net
Tyler Wayne
Tyler Wayne

Reputation: 363

How to add a new item to dropdownlist when no records are found in database

How can I add an alternative item to dropdownlist when no items are found in mysql database.

Here's what I've tried

Sub getstudent()
        Try
            Dim val As String = System.Configuration.ConfigurationManager.ConnectionStrings("val").ConnectionString
            Using mycon As New MySqlConnection(val)
                Using ds As New DataTable
                    mycon.Open()
                    Dim SQL As String = "SELECT reg_no, name FROM tbl_students where class='" & Dpclass.SelectedItem.Text & "' and sub_class='" & Dpsub_class.SelectedItem.Text & "' and acad_session='" & acad_session.SelectedItem.Text & "'"
                    Dim myCommand As New MySqlCommand(SQL, mycon)
                    Dim myDA As New MySqlDataAdapter
                    myDA.SelectCommand = myCommand
                    myDA.Fill(ds)
                    mycon.Close()

                    Dpname.DataSource = ds
                    Dpname.DataTextField = "name"
                    Dpname.DataValueField = "reg_no"
                    Dpname.DataBind()
                    If Dpname.DataTextField < 1 Then
                        Dpname.Text = "Nothing Found"
                    End If
                    Dpname.Items.Insert(0, New ListItem("-select-", "0"))
                End Using
            End Using
        Catch ex As Exception
            MsgBox(ex.Message)
        End Try
    End Sub

I'm getting an error: conversion from string "name" to type 'Double' is not valid.

Upvotes: 1

Views: 107

Answers (3)

Tyler Wayne
Tyler Wayne

Reputation: 363

I finally got it, thanks to Mahdy Aslamy

If ds.rows.count  = 0 then
    Dpname.items.insert(0, New ListItem("No records Found", "0"))
Else
    Dpname.items.insert(0, New ListItem("-Select-, "0""))
End If

Upvotes: 0

Edney Holder
Edney Holder

Reputation: 1228

I cannot be sure this is the answer since I do not know the structure of the table you are using but from what I see and the error given it appears you are adding 0 as a string and it is expecting a double. try the following:

Dpname.Items.Insert(0, New ListItem("-select-", 0))

Upvotes: 1

Mahdi Aslami Khavari
Mahdi Aslami Khavari

Reputation: 1985

check your DataTable is empty fill it with another value:

If ds.Rows.Count = 0 Then
    Dpname.DataSource = new DataTable()
End If

Upvotes: 2

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