Vb.net下一个和上一个按钮代码

Question

I am making a vb.net crud web application. I do not want to use any grid rather want to fetch records from sql database into text boxes. So far I have succeeded to show a record in a text box on pressing a button from the sql database. Now my question is can we design a next and previous button which would show next or previous records from sql database. It would be great if any body can share code to do this.

Below is my code to fetch a single record in the textbox

Protected Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
     Dim myConn As SqlConnection = New     SqlConnection("Server=.\SQLEXPRESS;AttachDbFilename=D:\MyFolder\MyDatabaseData.mdf;Integrated Security=True;Connect Timeout=30;User Instance=True")

    Dim dt As New DataTable
    Dim a As Integer
    a = 2

    Try
        myConn.Open()

        Dim SelectCommand As New SqlClient.SqlCommand("SELECT names FROM enames", myConn)

        txtOEID.Text = CStr(SelectCommand.ExecuteScalar())
        MsgBox("data is selected and show in the textbox and the connection is also closing")
        myConn.Close()


    Catch ex As Exception
        MsgBox(ex.ToString())
            End Try

End Sub

Answer 1

You can use where clause.

For example in your table you have : id (integer), last_name (char), first_name(char). All that you have to do is to "play" with select command. Your select will be like: "select * from aTable where id between first_index and last_index" . first_index and last_index are limits of records that you want to fetch, and in buttons action you have to increment/decrement that indexes.

Another solution can be copying values that you obtain into a list.

Good luck.

Answer 2

if you already have datatable, you can continue with datarow from the table

Dim dr As Datarow 

dr = dt.rows(currentRowIndex)
txtName = dr.item("name")
txtProf = dr.item("profession")

etc 

Hope it helps !