DataBind

public static bool DataBind(this ListControl control, object datasource, string textField, string valueField)
{
    return DataBind(control, datasource, textField, null, valueField);
}

public static bool DataBind(this ListControl control, object datasource, string textField, string textFieldFormat, string valueField)
{
    control.DataTextField = textField;
    control.DataValueField = valueField;

    if (!string.IsNullOrEmpty(textFieldFormat))
        control.DataTextFormatString = textFieldFormat;

    control.DataSource = datasource;
    control.DataBind();

    if (control.Items.Count > 0)
    {
        control.SelectedIndex = 0;
        return true;
    }
    else return false;
}

Dictionary<int, string> data = new Dictionary<int,string>();
data.Add(0,"Apple");
data.Add(1,"Orange");
data.Add(2,"Pair");

DropDownList ddl = new DropDownList();
ddl.DataBind(data, "value", "key");

ListBox lbx = new ListBox();
lbx.DataBind(data, "value", "key");