Has anybody seen anything on a custom gridview with builtin alpha paging - asp.net

Question

I have a a custom gridview control that I like to incorpoarate different features as I come across them. Is there a way to access the datasource and the method being used to update the data with clicked letter? I have figured out how to create the alpha links in the footer like so
Protected Overloads Overrides Sub OnRowCreated(ByVal e As GridViewRowEventArgs)
MyBase.OnRowCreated(e)
If e.Row.RowType = DataControlRowType.Footer Then
Dim intNoOfMergeCol As Integer = e.Row.Cells.Count
'except last column
For intCellCol As Integer = intNoOfMergeCol - 1 To 1 Step -1
e.Row.Cells.RemoveAt(intCellCol)
Next
e.Row.Cells(0).ColumnSpan = Me.HeaderRow.Cells.Count
For i As Integer = 65 To (65 + 25)
Dim lb As LinkButton = New LinkButton()
lb.Text = Char.ConvertFromUtf32(i) & " "
lb.CommandArgument = Char.ConvertFromUtf32(i)
lb.CommandName = "AlphaPaging"
e.Row.Cells(0).Controls.Add(lb)
Next
e.Row.Cells(0).HorizontalAlign = HorizontalAlign.Left
End If
End Sub
I can use the rowCommand event to check for the click like so
Protected Overloads Overrides Sub OnRowCommand(ByVal e As System.Web.UI.WebControls.GridViewCommandEventArgs)
If e.CommandName = "AlphaPaging" Then
'todo
End If
End Sub
But I am unsure of where to get the data information needed to make the functionality work. Any clues will be very much appreciated

Answer 1

I don't think I would try and add such a filter or setup to the GV.
I would simple drop the filter below the GV.
And that will save a LOT of work. Better yet, we can use say a control like RadioButton list.
Why?
Well a radio button list automatic ONLY allows one choice, and thus clicking on one letter will highlight, and un-highlight for us automatic.
more why?
The RadioButton list has ONE event - so we don't have to write/wire up a whole bunch of buttons to one event - it done for use
more more why?
RadioButton list, like all asp.net controls can be feed data - just like most controls - so we follow the design pattern to fill out that control like anything else.
more more more why?
We can flip the RadioButton list over to a check box - and now we have multiple filters as possible.
So, say we have this simple grid:
<div style="width:60%;padding-25px">
<br />
<asp:GridView ID="GridView1" runat="server"
AutoGenerateColumns="False" DataKeyNames="ID" CssClass="table">
<Columns>
<asp:BoundField DataField="FirstName" HeaderText="FirstName" />
<asp:BoundField DataField="LastName" HeaderText="LastName" />
<asp:BoundField DataField="HotelName" HeaderText="HotelName" />
<asp:CheckBoxField DataField="Active" HeaderText="Active" />
<asp:BoundField DataField="Description" HeaderText="Description" />
</Columns>
</asp:GridView>
</div>
Ok, code to fill is this:
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
If Not IsPostBack Then
LoadGrid
End If
End Sub
Sub LoadGrid()
Using conn As New SqlConnection(My.Settings.TEST4)
Dim strSQL As String =
"SELECT * FROM tblHotels ORDER BY HotelName"
Using cmdSQL As New SqlCommand(strSQL, conn)
conn.Open()
Dim rstData As New DataTable
rstData.Load(cmdSQL.ExecuteReader)
GridView1.DataSource = rstData
GridView1.DataBind()
End Using
End Using
End Sub
And we now have this:
so, now lets drop in a RadioButton ist - right below the grid.
(I don't think trying to put inside the GV is worth the efforts).
So, we add this mark up -
</asp:GridView>
<div style="border:solid;border-color:black;border-width:1px;padding:5px;margin-top:-12px">
<asp:RadioButtonList ID="RadioAlpha" runat="server"
AppendDataBoundItems="True"
RepeatDirection="Horizontal"
DataTextField="Value"
DataValueField="Key" CssClass="rMyChoice"
AutoPostBack="true">
</asp:RadioButtonList>
So, we drop in that radio button list.
Now, in load grid to the above code, we have this:
Dim bList As New Dictionary(Of Integer, String)
For i As Integer = Asc("A") To Asc("Z")
bList.Add(i, Chr(i))
Next
bList.Add(0, "All") ' we need a "all/no filter"
' bind this to our radio button list
RadioAlpha.DataSource = bList
RadioAlpha.DataBind()
RadioAlpha.SelectedValue = 0
And with that style sheet - we hide the radio button - so only letter shows, and we now have this
And now the filter code is easy - we have ONE RadioButton event, and our code can be this:
Protected Sub RadioAlpha_SelectedIndexChanged(sender As Object, e As EventArgs) Handles RadioAlpha.SelectedIndexChanged
Using conn As New SqlConnection(My.Settings.TEST4)
Dim strSQL As String = "SELECT * FROM tblHotels"
Using cmdSQL As New SqlCommand(strSQL, conn)
conn.Open()
If RadioAlpha.SelectedItem.Text <> "All" Then
cmdSQL.CommandText &= " WHERE HotelName like #H + '%' "
cmdSQL.Parameters.Add("#H", SqlDbType.NVarChar).Value = RadioAlpha.SelectedItem.Text
End If
cmdSQL.CommandText &= " ORDER BY HotelName"
Dim rstData As New DataTable
rstData.Load(cmdSQL.ExecuteReader)
GridView1.DataSource = rstData
GridView1.DataBind()
End Using
End Using
End Sub
So, click on a letter, we get this:
So not only is the filter code quite easy, but MORE imporant, is the "B" button highlights for us, only one button can be clicked.
So, I don't think I would shove such a filter into the GV.
And we can add/turn on data paging for the above. After all, hitting "all" or some letter certainly could produce more then a page of data.