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Change items in ComboBox after button click

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ComboBox
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JP
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JP asked on 11 May 2012, 09:36 AM
Hi,

normally you have to populate the ComboBox in OnInit so the items are persisted after postback. But I need to populate the combobox after a button was clicked. Initially the comboBox could be empty, but after the button click I want to populate the combobox in a way that the items are persisted between postbacks.

How could I achieve this?

Thanks!

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Princy
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answered on 15 May 2012, 01:36 PM
Hi,

I suppose that you want to populate the RadComboBox in the onClick event of Button. The RadComboBoxItems are persisting in my side after postbacks. Here is the full code that I tried.

ASPX:
<telerik:RadComboBox ID="RadComboBox1" runat="server" >
</telerik:RadComboBox>
<asp:Button ID="Button1" runat="server" onclick="button1_onClick" />

C#:
protected void button1_onClick(object sender, EventArgs e)
    {
        string connectionString = WebConfigurationManager.ConnectionStrings["NorthwindConnectionString"].ConnectionString;
        SqlConnection con = new SqlConnection(connectionString);
        SqlDataAdapter adapter = new SqlDataAdapter("SELECT Text,Value FROM Table", con);
        DataTable dt = new DataTable();
        adapter.Fill(dt);
        RadComboBox1.DataTextField = "Text";
        RadComboBox1.DataValueField = "Value";
        RadComboBox1.DataSource = dt;
        RadComboBox1.DataBind();
    }

Please elaborate your scenario and provide your full code if it doesn't help.

Regards,
Princy.
0
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Ivana
Telerik team
answered on 15 May 2012, 01:51 PM
Hello Jan,

Try the following:
<telerik:RadButton runat="server" ID="RadButton2"  Text="Postback"/>
<telerik:RadButton runat="server" ID="RadButton1" OnClick="RadButton1_Click" Text="Populate Combo"/>
<telerik:RadComboBox runat="server" ID="RadComboBox1">
</telerik:RadComboBox>
protected void Page_Load(object sender, EventArgs e)
{
    if (Session["Populated"] == "populated")
    {
        RadComboBox1.Items.Add(new RadComboBoxItem("111", "111"));
        RadComboBox1.Items.Add(new RadComboBoxItem("222", "222"));
        RadComboBox1.Items.Add(new RadComboBoxItem("333", "333"));
    }
}
 
protected void RadButton1_Click(object sender, EventArgs e)
{
    if (Session["Populated"] == null)
    {
        RadComboBox1.Items.Add(new RadComboBoxItem("111", "111"));
        RadComboBox1.Items.Add(new RadComboBoxItem("222", "222"));
        RadComboBox1.Items.Add(new RadComboBoxItem("333", "333"));
        Session["Populated"] = "populated";
    }
}

I hope it will help.

Kind regards,
Ivana
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ComboBox
Asked by
JP
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Answers by
Princy
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Ivana
Telerik team
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