DataGrid.PageIndexChanged not firing on when 0th page requested
- From: Marc Woolfson <MarcWoolfson@xxxxxxxxxxxxxxxxxxxxxxxxx>
- Date: Wed, 23 May 2007 03:11:01 -0700
Hello,
I have a Web Part that contains a relatively simple DataGrid, paginated
across four pages. Switching between pages 2, 3 and 4 works fine, but if you
request the first (0th) page again, the PageIndexChanged event does not fire.
Please see my code below:
1 public class ListOfDataWebPart : WebPart
2 {
3
4 protected DataGrid TestDataGrid;
5 protected DataSet pt_dgData;
6
7 /// <summary>
8 /// Prepare data to display in the datagrid on first page request
9 /// </summary>
10 /// <param name="e"></param>
11 protected override void OnLoad(EventArgs e)
12 {
13 base.OnLoad(e);
14
15 if (!this.Page.IsPostBack)
16 {
17 pt_dgData = GetDataSource();
18 ViewState["dgData"] = pt_dgData;
19 }
20 }
21
22 /// <summary>
23 /// Render the web part, and controls contained therein
24 /// </summary>
25 /// <param name="writer"></param>
26 protected override void Render(System.Web.UI.HtmlTextWriter
writer)
27 {
28 this.Title = "List of Data";
29 this.AllowClose = false;
30 this.AllowMinimize = false;
31 this.AllowEdit = false;
32
33 TestDataGrid.RenderControl(writer);
34
35 writer.Write("Current page shown in grid: " +
TestDataGrid.CurrentPageIndex);
36 }
37
38 /// <summary>
39 /// Add additional controls to the web part
40 /// </summary>
41 protected override void CreateChildControls()
42 {
43 GetDataGrid();
44
45 base.CreateChildControls();
46 }
47
48 /// <summary>
49 /// Create, populate, event handle and stylise the datagrid
control
50 /// </summary>
51 private void GetDataGrid()
52 {
53 // core grid
54 TestDataGrid = new DataGrid();
55 TestDataGrid.ID = "TestDG";
56 TestDataGrid.AllowPaging = true;
57 TestDataGrid.PageSize = 5;
58 TestDataGrid.PagerStyle.Mode = PagerMode.NumericPages;
59 TestDataGrid.AutoGenerateColumns = false;
60 TestDataGrid.EnableViewState = true;
61
62 // styles
63 TestDataGrid.CellPadding = 1;
64 TestDataGrid.GridLines = GridLines.None;
65 TestDataGrid.Width = new Unit(100, UnitType.Percentage);
66 TestDataGrid.ItemStyle.CssClass = "ms-vb2";
67 TestDataGrid.AlternatingItemStyle.CssClass =
"ms-alternating ms-vb2";
68 TestDataGrid.HeaderStyle.CssClass = "ms-vh2-nofilter";
69 TestDataGrid.PagerStyle.CssClass = "ms-menutoolbar
ms-toolbar";
70 TestDataGrid.PagerStyle.HorizontalAlign =
HorizontalAlign.Right;
71
72 // events
73 TestDataGrid.PageIndexChanged += new
DataGridPageChangedEventHandler(TestDataGrid_PageIndexChanged);
74
75 // columns
76 BoundColumn l_idCol = new BoundColumn();
77 l_idCol.HeaderText = "ID";
78 l_idCol.DataField = "ID";
79 TestDataGrid.Columns.Add(l_idCol);
80
81 BoundColumn l_ValueCol = new BoundColumn();
82 l_ValueCol.HeaderText = "Value";
83 l_ValueCol.DataField = "Value";
84 TestDataGrid.Columns.Add(l_ValueCol);
85
86 // rendering
87 RebindDG();
88 this.Controls.Add(TestDataGrid);
89 }
90
91 /// <summary>
92 /// Change the page displayed within the datagrid control
(seemingly fails to execute when 0th page requested)
93 /// </summary>
94 /// <param name="source"></param>
95 /// <param name="e"></param>
96 protected void TestDataGrid_PageIndexChanged(Object source,
DataGridPageChangedEventArgs e)
97 {
98 this.Page.Response.Write("New page requested from grid: " +
e.NewPageIndex);
99 TestDataGrid.CurrentPageIndex = e.NewPageIndex;
100 RebindDG();
101 }
102
103 /// <summary>
104 /// Rebind the datagrid to the data held in ViewState
105 /// </summary>
106 private void RebindDG()
107 {
108 pt_dgData = (DataSet)ViewState["dgData"];
109
110 TestDataGrid.DataSource = pt_dgData;
111 TestDataGrid.DataBind();
112 }
113
114 /// <summary>
115 /// Create a dummy dataset to test the control
116 /// </summary>
117 /// <returns>The DataSet to bind to the grid</returns>
118 private DataSet GetDataSource()
119 {
120 DataSet l_ds = new DataSet();
121 DataTable l_dt = new DataTable();
122 DataRow l_row;
123
124 l_dt.Columns.Add("ID", typeof(int));
125 l_dt.Columns.Add("Value", typeof(string));
126
127 // create 20 entries with the row number in the ID column
and a random string in the Value column
128 for (int i = 0; i < 20; i++)
129 {
130 l_row = l_dt.NewRow();
131 l_row[0] = i;
132 l_row[1] = Guid.NewGuid().ToString();
133 l_dt.Rows.Add(l_row);
134 }
135 l_ds.Tables.Add(l_dt);
136
137 return l_ds;
138 }
139
140 }
Writing the values back to the screen show that when the nth page is
requested the messages show the correct values, but the 0th page only shows
the current page number, not the requested one as well.
I have seen a few articles on problems with this event not firing at all,
but this doesn't seem to be my issue. The one post I found that seemed to
match this problem didn't have a reply :'( . Does anyone have any pointers?
Thanks,
Marc
.
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