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How to retrieve dataitem

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ComboBox

This is a migrated thread and some comments may be shown as answers.

18 Answers, 1 is accepted

answered on 05 May 2009, 05:34 PM

Sorry if I wasnt clear but that wasnt the answer I was looking for.

Assume I have the following DataTable. My when I bind the DataTable to the combobox, and if the index is changed, How do I get the DataRow back without using any other global temporary datatable variable to refer the position. When I call

myCombobox.SelectedItem.DataItem

the dataitem is always null... if my selectedItem.Text == "Bob", I want the DataItem to return the DataRow like dr as below... so I can get the dr["Address"] = "123 Ave" address. Any ideas?

    
            //In aspx 
        
            <telerik:RadComboBox ID="myCombobox" runat="server" Filter="Contains"  
        
            DataTextField="Name" DataValueField="ID" Width="220"> 
        
            </telerik:RadComboBox> 
        
            //In code 
        
            DataTable dt = new DataTable(); 
        
            dt.Columns.Add(new DataColumn("ID", typeof(string))); 
        
            dt.Columns.Add(new DataColumn("Name", typeof(string))); 
        
            dt.Columns.Add(new DataColumn("Address", typeof(DateTime))); 
        
            DataRow dr = dt.NewRow(); 
        
            dr["ID"] = "12345"; 
        
            dr["Name"] = "Bob"; 
        
            dr["Address"] = "123 Ave"; 
        
            dt.Rows.Add(dr); 
        
            DataRow dr2 = dt.NewRow(); 
        
            dr2["ID"] = "6123"; 
        
            dr2["Name"] = "Mary"; 
        
            dr2["Address"] = "123 Ave #333"; 
        
            dt.Rows.Add(dr2); 
        
            myCombobox.Datasource = dt; 
        
            myCombobox.DataBind(); 
        
            //on mycombobox index changed 
        
            protected void myCombobox_OnSelectedIndexChanged(object sender, RadComboBoxSelectedIndexChangedEventArgs e) 
        
            { 
        
              DataRow dr = myCombobox.SelectedItem.DataItem as DataRow; 
        
            }

answered on 17 Feb 2010, 12:29 PM

Hello,

Please take a look at the following example based on previously posted code:

<telerik:RadComboBox ID="myCombobox" runat="server" Filter="Contains"

AutoPostBack="true" DataTextField="Name" DataValueField="ID" Width="220"

OnSelectedIndexChanged="myCombobox_OnSelectedIndexChanged">

</telerik:RadComboBox>

protected void Page_Load(object sender, EventArgs e)

{

if (!IsPostBack)

{

DataTable dt = new DataTable();

dt.Columns.Add(new DataColumn("ID", typeof(string)));

dt.Columns.Add(new DataColumn("Name", typeof(string)));

dt.Columns.Add(new DataColumn("Address", typeof(string)));

DataRow dr = dt.NewRow();

dr["ID"] = "12345";

dr["Name"] = "Bob";

dr["Address"] = "123 Ave";

dt.Rows.Add(dr);

DataRow dr2 = dt.NewRow();

dr2["ID"] = "6123";

dr2["Name"] = "Mary";

dr2["Address"] = "123 Ave #333";

dt.Rows.Add(dr2);

myCombobox.DataSource = dt;

myCombobox.DataBind();

}

protected void myCombobox_OnSelectedIndexChanged

(object o, Telerik.Web.UI.RadComboBoxSelectedIndexChangedEventArgs e)

{

RadComboBoxItem item = myCombobox.FindItemByValue(e.Value);

}

Note the way RadComboBoxItem is retrieved. More about RadComboBoxItems you can find here.

Another important issue is that the SelectedIndexChanged event does not fire unless the AutoPostBack property is True - more about this topic find in this article.

Of course if you prefer to add more properties to an item, you can use Attributes collection to store them.

Best regards,
Kalina
the Telerik team

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answered on 01 Mar 2010, 03:25 PM

Hi Arnstein,

Thank you for the clarification.

I suggest you use the Attributes collection of RadComboBoxItems. You can use this collection to expand the information stored in them.

I made a few changes to your code to illustrate this approach:

protected void Page_Load(object sender, EventArgs e)

{

if (!IsPostBack)

{

DataTable dt = new DataTable();

dt.Columns.Add(new DataColumn("ID", typeof(string)));

dt.Columns.Add(new DataColumn("Name", typeof(string)));

dt.Columns.Add(new DataColumn("Address", typeof(string)));

DataRow dr = dt.NewRow();

dr["ID"] = "12345";

dr["Name"] = "Bob";

dr["Address"] = "Address 1";

dt.Rows.Add(dr);

DataRow dr2 = dt.NewRow();

dr2["ID"] = "6123";

dr2["Name"] = "Mary";

dr2["Address"] = "Address 2";

dt.Rows.Add(dr2);

foreach (DataRow dataRow in dt.Rows)

{

RadComboBoxItem item = new RadComboBoxItem();

item.Text = (string)dataRow["Name"];

item.Value = dataRow["ID"].ToString();

item.Attributes.Add("Address", dr["Address"].ToString());

myCombobox.Items.Add(item);

item.DataBind();

}

protected void myCombobox_OnSelectedIndexChanged

(object o, Telerik.Web.UI.RadComboBoxSelectedIndexChangedEventArgs e)

{

RadComboBoxItem item = myCombobox.FindItemByValue(e.Value);

string address = item.Attributes["Address"];

}

Best wishes,
Kalina
the Telerik team