Storing Temporary Data : VB.NET & ASP.NET : Using DataTable & GirdView


step 1:Create Temporary DataTable &
Add a GridView control, two lable controls, three textbox controls and
button control in the page .

Private Function CreateTempDataTable() As DataTable
Dim myDataTable As DataTable = New DataTable()

Dim myDataColumn As DataColumn

myDataColumn = New DataColumn()
myDataColumn.DataType = Type.GetType("System.String")
myDataColumn.ColumnName = "id"
myDataTable.Columns.Add(myDataColumn)

myDataColumn = New DataColumn()
myDataColumn.DataType = Type.GetType("System.String")
myDataColumn.ColumnName = "username"
myDataTable.Columns.Add(myDataColumn)

myDataColumn = New DataColumn()
myDataColumn.DataType = Type.GetType("System.String")
myDataColumn.ColumnName = "firstname"
myDataTable.Columns.Add(myDataColumn)

myDataColumn = New DataColumn()
myDataColumn.DataType = Type.GetType("System.String")
myDataColumn.ColumnName = "lastname"
myDataTable.Columns.Add(myDataColumn)

Return myDataTable
End Function

Step 2:

Private Function PoputlateDataTable(ByVal username As String, ByVal
firstname As String,

ByVal lastname As String, ByVal myTable As DataTable)
Dim row As DataRow

row = myTable.NewRow()

row("id") = Guid.NewGuid().ToString()
row("username") = username
row("firstname") = firstname
row("lastname") = lastname

myTable.Rows.Add(row)
End Function



Now call the PopulateDataTable Function :

Private Sub Some ClickEvent_XXX()

If txtUserName.Text.Trim() = "" Then
Me.lblTips.Text = "You must fill a username."
Return
Else
AddDataToTable(Me.txtUserName.Text.Trim(), Me.txtFirstName.Text.Trim(),

Me.txtLastName.Text.Trim(), CType(Session("myDatatable"), DataTable))

Me.GridView1.DataSource = CType(Session("myDatatable"),
DataTable).DefaultView

Me.GridView1.DataBind()

Me.txtFirstName.Text = ""
Me.txtLastName.Text = ""
Me.txtUserName.Text = ""
Me.lblTips.Text = ""
End If

End Sub



Important Note:

Please note that "Session["myDatatable"] = myDt;" is important to ensure we
can add new data

continually until the page be closed.


Private Sub Page_Load(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles

Me.Load
If Me.IsPostBack = False Then
myDt = New DataTable()
myDt = CreateTempDataTable()
Session("myDatatable") = myDt

Me.GridView1.DataSource = (CType(Session("myDatatable"),
DataTable)).DefaultView
Me.GridView1.DataBind()
End If
End Sub