[Solved] Row Null problem

[he seaman]

I have binding the gridview's itemsource, and it works right,but I need do some others work when i click the button,the problem is coming,
the gridview's row alway diaplay null??  why

 public partial class MainPage : UserControl
    {
        ObservableCollection<dynamic> obList = null;
       
        string sb = "";

        public MainPage()
        {
            InitializeComponent();
            WCFTestClient wcf = new WCFTestClient();
            wcf.GetDataAsync();
            wcf.GetDataCompleted += new EventHandler<GetDataCompletedEventArgs>(wcf_GetDataCompleted);
         
        }

         
           void wcf_GetDataCompleted(object sender, GetDataCompletedEventArgs e)
        {

            obList = DataTableHelp.getListByDataTableStr(e.Result);

            gridMain.ItemsSource = obList;
          
            for (int i = 0; i < gridMain.Columns.Count; i++)
            {
                System.Windows.Controls.ComboBoxItem comboItem = new ComboBoxItem();
                comboItem.Content = gridMain.Columns[i].UniqueName;

                col1.Items.Add(comboItem);
            }
         

       }

        private void Button_Click(object sender, RoutedEventArgs e)
        {
              DataTable dt = new DataTable();
                     
              
            foreach (var column in gridMain.Columns)
            {
                GridViewDataColumn dataColumn = column as GridViewDataColumn;
                DataColumn dc = new DataColumn();
                if (dataColumn != null)
                {
                    dc.ColumnName = dataColumn.UniqueName;
                    dc.DataType = dataColumn.DataType;
                    dt.Columns.Add(dc);
                }
            }

            dt.Columns.Add(new DataColumn() { ColumnName = "RS", DataType = typeof(double) }); 
           
              foreach (var item in this.gridMain.Items)
            {

                string s = txt_rs.Text;
                GridViewRow row = this.gridMain.ItemContainerGenerator.ContainerFromItem(item) as GridViewRow;
                DataRow pr = new DataRow();
                if (row != null)
                {

                    foreach (GridViewCell cell in row.Cells)
                    {

                        if (cell.Column.UniqueName != "RS")
                        {
                            pr[cell.Column.UniqueName] = cell.Value;
                            string t = "";
                            if (cell.Value.ToString() == "" || cell.Value == null)
                            {
                                t = "(0)";
                            }
                            else
                            {
                                t = cell.Value.ToString().Trim();
                                if (t.First().ToString().Trim() == "-")
                                {
                                    t = "(0" + t + ")";
                                }

                            }
                            s = Replace(s, cell.Column.UniqueName, t);
                        }

                    }
                    pr["RS"] = this.cal(s);
                    dt.Rows.Add(pr);

               }

            }
          
                  
            gridMain.ItemsSource = dt.ToList();         

        }

the dt.rows.count is not same the gridMain.Items.count
pls help me ,thanks a lot

[Veselin Vasilev]

Hi he seaman,

This is a normal behavior because of the row virtualization. The grid.Items contains all the items in the grid (in or out of the viewport). The line:
GridViewRow row = this.gridMain.ItemContainerGenerator.ContainerFromItem(item) as GridViewRow;

will work only for the rows that are in the viewport. For all other items the row will be null.

You can try to switch off the row virtualization and see if it behaves the way you expect.

All the best,
Veselin Vasilev
the Telerik team