i am having two list box which perform add remove item functionality which are controlled by four buttons and o each button click there happen to be post back but i don't want it to be flicker for which i am using update panel like this but it still made post back wats wrong with this explain me this
<asp:UpdatePanel ID="button" runat="server" UpdateMode="Always">
<ContentTemplate>
<asp:Button ID="ButtonAdd" runat="server" Text=">" OnClick="ButtonAdd_Click" Width="50px"/><br />
<asp:Button ID="ButtonRemove" runat="server" Text="<" OnClick="ButtonRemove_Click" Width="50px"/><br />
<asp:Button ID="ButtonAddAll" runat="server" Text =">>>" OnClick="ButtonAddAll_Click" Width="50px"/><br />
<asp:Button ID="ButtonRemoveAll" runat="server" Text ="<<<" OnClick="ButtonRemoveAll_Click" Width="50px"/>
</ContentTemplate>
</asp:UpdatePanel>
I wrote a quick example that does work. You do not need your buttons in the UpdatePanel
. You only need the ListBox
since they are the only controls being refresh. Setup the Trigger
for the UpdatePanel
will cause the refreshes to occur without the 'flicker'.
aspx code:
<asp:ScriptManager ID="ScriptManager1" runat="server" />
<div>
<asp:Button ID="ButtonAdd" runat="server" Text=">" OnClick="ButtonAdd_Click" Width="50px"/><br />
<asp:Button ID="ButtonRemove" runat="server" Text="<" OnClick="ButtonRemove_Click" Width="50px"/><br />
<asp:Button ID="ButtonAddAll" runat="server" Text =">>>" OnClick="ButtonAddAll_Click" Width="50px"/><br />
<asp:Button ID="ButtonRemoveAll" runat="server" Text ="<<<" OnClick="ButtonRemoveAll_Click" Width="50px"/>
<asp:UpdatePanel ID="button" runat="server" UpdateMode="Always">
<Triggers>
<asp:AsyncPostBackTrigger ControlID="ButtonAdd" EventName="Click" />
<asp:AsyncPostBackTrigger ControlID="ButtonRemove" EventName="Click" />
<asp:AsyncPostBackTrigger ControlID="ButtonAddAll" EventName="Click" />
<asp:AsyncPostBackTrigger ControlID="ButtonRemoveAll" EventName="Click" />
</Triggers>
<ContentTemplate>
<asp:ListBox ID="ListBox1" runat="server"></asp:ListBox>
<asp:ListBox ID="ListBox2" runat="server"></asp:ListBox>
</ContentTemplate>
</asp:UpdatePanel>
</div>
cs (codebehind) code:
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
ListBox1.Items.Add(new ListItem("Test1", "1"));
ListBox1.Items.Add(new ListItem("Test2", "2"));
ListBox1.Items.Add(new ListItem("Test3", "3"));
ListBox1.Items.Add(new ListItem("Test4", "4"));
ListBox1.Items.Add(new ListItem("Test5", "5"));
}
}
protected void ButtonRemove_Click(object sender, EventArgs e)
{
if (ListBox2.SelectedItem != null)
{
ListBox1.Items.Add(ListBox2.SelectedItem);
ListBox2.Items.RemoveAt(ListBox2.SelectedIndex);
ListBox2.ClearSelection();
ListBox1.ClearSelection();
}
}
protected void ButtonAdd_Click(object sender, EventArgs e)
{
if (ListBox1.SelectedItem != null)
{
ListBox2.Items.Add(ListBox1.SelectedItem);
ListBox1.Items.RemoveAt(ListBox1.SelectedIndex);
ListBox1.ClearSelection();
ListBox2.ClearSelection();
}
}
I have tested this and it does work. I only implemented 2 of the Button
s to present a complete example.