Introduction
When I try to create dynamic controls in gridview like (label, textbox, checkbox, etc.) lose my controls when the page is posted back. When I tried to find a solution on the internet I didn't find any so I decided to solve it by myself.
Problem Definition
- First I add TemplateColumn To gridview
- Then I but in (ItemTemplate) PlaceHolder control:
<asp:GridView ID="GridView1" runat="server" DataSourceID="ObjectDataSource1"
AutoGenerateColumns="False" OnRowDataBound="GridView1_RowDataBound"
OnDataBinding="GridView1_DataBinding" OnDataBound="GridView1_DataBound">
<Columns>
<asp:TemplateField>
<ItemTemplate>
<asp:Label ID="Label1" runat="server" Text='<%# Bind("RoomID") %>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField>
<ItemTemplate>
<asp:PlaceHolder ID="PlaceHolder1" runat="server"
OnPreRender="PlaceHolder1_PreRender"></asp:PlaceHolder>
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
Then the code that will create the controls based in DataBase Filed (RoomID) in the event RowDataBound as follows:
protected void GridView1_RowDataBound(object sender,GridViewRowEventArgs e) {
PlaceHolder plc = (PlaceHolder)e.Row.Cells[1].FindControl("PlaceHolder1");
Label lbl_RoomID = (Label)e.Row.Cells[0].FindControl("Label1");
Label lblinsert = new Label();
CheckBox chk = new CheckBox();
TextBox txt = new TextBox();
chk.Text = "tttttttt";
lblinsert.Text = "xxxxxxxxx";
if (lbl != null)
{
switch(lbl.Text)
{
case "1":plc.Controls.Add(lblinsert);
arr.Add(lblinsert);break;
case "2":plc.Controls.Add(chk);
arr.Add(chk);break;
case "3": plc.Controls.Add(txt);
arr.Add(txt); break;
default: lblinsert.Text = " Dummy ";
plc.Controls.Add(lblinsert);
arr.Add(lblinsert); break;
}
}
}
}
The Solution
When I creat controls in event RowDataBound I add them to ArrayList then at event DataBound I but ArrayList In Session
protected void GridView1_DataBound(object sender, EventArgs e)
{
Session.Add("arrcon", arr);
}
Then at the PlaceHolder_PreRender event I got ArrayList and recreate controls into it again with its data
Int count = 0 ;
protected void PlaceHolder1_PreRender(object sender, EventArgs e)
{
if (Page.IsPostBack)
{
arr = (ArrayList)Session["arrcon"];
if (arr != null)
{
if (arr[count] is TextBox)
{
TextBox txt = (TextBox)arr[count];
txt.Text = Request.Form[txt.UniqueID].ToString();
((PlaceHolder)this.GridView1.Rows[count].Cells[1].FindControl(
"PlaceHolder1")).Controls.Add(txt);
}
else if (arr[count] is Label)
{
((PlaceHolder)this.GridView1.Rows[count].Cells[1].FindControl(
"PlaceHolder1")).Controls.Add((Control)arr[count]);
}
else if (arr[count] is CheckBox)
{
CheckBox chk = (CheckBox)arr[count];
if (Request.Form[chk.UniqueID] != null)
{
chk.Checked = true;
}
else
{
chk.Checked = false;
}
((PlaceHolder)this.GridView1.Rows[count].Cells[1].FindControl(
"PlaceHolder1")).Controls.Add(chk);
}
count++;
}
}
}
And this solved my problem
