datagridusing System;
using System.Web.UI.WebControls;
using System.Data;


/*
*    The Control assumes the following:
*
*        1) It is bound to a DataView object.
*        2) The app will use direct SQL commands to update the source (NO batch update).
*        3) No custom paging is enabled.
*        
*      If you plan to support sorting, then some aspects of this code should be reviewed
*      and adapted.
*
*/

namespace BWSLib
{
    namespace Controls
    {
        public class EditableGrid : DataGrid
        {
            // Constructor that sets some styles and graphical properties    
            public EditableGrid()
            {
                AllowFullEditing = true;
                AddNewRow = false;
                RejectChanges = false;
                MustInsertRow = false;

                AllowPaging = true;

                // Handlers
                Init += new EventHandler(OnInit);
                PageIndexChanged += new DataGridPageChangedEventHandler(OnPageIndexChanged);

                ItemCreated += new DataGridItemEventHandler(OnItemCreated);
                CancelCommand += new DataGridCommandEventHandler(OnCancelCommand);
                EditCommand += new DataGridCommandEventHandler(OnEditCommand);
                UpdateCommand += new DataGridCommandEventHandler(OnUpdateCommand);
                DeleteCommand += new DataGridCommandEventHandler(OnDeleteCommand);
            }


            // PROPERTY: AllowFullEditing
            // Enable full editing
            public bool AllowFullEditing;

            // PROPERTY: AddNewRow
            // if true must add an empty row at the bottom of the data source
            public bool AddNewRow;
        
            // INTERNAL PROPERTY: RejectChanges
            // if true must reject changes on the last row of the data source
            protected bool RejectChanges;

            // INTERNAL PROPERTY: MustInsertRow
            // if true must INSERT instead of UPDATE and there's a pending change
            protected bool MustInsertRow
            {
                get {return Convert.ToBoolean(ViewState["MustInsertRow"]);}
                set {ViewState["MustInsertRow"] = value;}
            }


            // PROPERTY: DataSource (override)
            public override object DataSource
            {
                get {return base.DataSource;}
                set
                {    
                    base.DataSource = value;
                    if (AllowFullEditing)
                    {
                        if (AddNewRow)
                        {
                            AddNewRow = false;
                            InsertNewRow();
                        }

                        if (AllowFullEditing && RejectChanges)
                        {
                            RejectChanges = false;
                            MustInsertRow = false;
                            RejectChangesOnLastRow();
                        }
                    }
                }
            }

    
            // PROPERTY: command columns
            public bool ShowWebdings = false;
            public String EditColumnText = "Edit";
            public String EditColumnUpdateText = "OK";
            public String EditColumnCancelText = "Cancel";
            public String DeleteColumnText = "Delete";


            // EVENT: InitRow
            public delegate void DataGridInitRowEventHandler(Object sender, DataGridInitRowEventArgs e);
            public event DataGridInitRowEventHandler InitRow;
            private void OnInitRow(DataGridInitRowEventArgs e)
            {
                if (InitRow != null)
                    InitRow(this, e);
            }


            // EVENT: UpdateView
            public event EventHandler UpdateView;
            protected virtual void OnUpdateView(EventArgs e)
            {
                if (UpdateView != null)
                    UpdateView(this, e);
            }
        

            // EVENT: SaveData
            public event DataGridCommandEventHandler SaveData;
            protected virtual void OnSaveData(DataGridCommandEventArgs e)
            {
                if (SaveData != null)
                    SaveData(this, e);
            }
        
        
            // EVENT: InsertData
            public event DataGridCommandEventHandler InsertData;
            protected virtual void OnInsertData(DataGridCommandEventArgs e)
            {
                if (InsertData != null)
                    InsertData(this, e);
            }
        

            // EVENT: DeleteData
            public event DataGridCommandEventHandler DeleteData;
            protected virtual void OnDeleteData(DataGridCommandEventArgs e)
            {
                if (DeleteData != null)
                    DeleteData(this, e);
            }
        

        
            // EVENT HANDLER: Init
            public void OnInit(Object sender, EventArgs e)
            {
                if (AllowFullEditing)
                    AddWorkerColumns();
            }


            // EVENT HANDLER: ItemCreated
            public void OnItemCreated(Object sender, DataGridItemEventArgs e)
            {
                ListItemType lit = e.Item.ItemType;
                if (lit == ListItemType.Item || lit == ListItemType.AlternatingItem)
                    CustomizeItem(e);
            }


            // EVENT HANDLER: CancelCommand
            public void OnCancelCommand(Object sender, DataGridCommandEventArgs e)
            {
                if (e.Item.ItemIndex == 0)
                    CurrentPageIndex = (CurrentPageIndex==0 ?0 :CurrentPageIndex-1);

                // Clears edit mode
                EditItemIndex = -1;

                // Reject changes on the last row
                RejectChanges = true;

                // Show/Hide DELETE column
                ToggleDeleteColumn(true);

                // Refresh view
                OnUpdateView(EventArgs.Empty);
            }


            // EVENT HANDLER: EditCommand
            public void OnEditCommand(Object sender, DataGridCommandEventArgs e)
            {
                // Reject changes on the last row (if any)
                RejectChanges = true;

                // Show/Hide DELETE column
                ToggleDeleteColumn(false);

                // Enable editing on the clicked row
                EditItemIndex = e.Item.ItemIndex;

                // Refresh view
                OnUpdateView(EventArgs.Empty);
            }


            // EVENT HANDLER: UpdateCommand
            public void OnUpdateCommand(Object sender, DataGridCommandEventArgs e)
            {
                // Clear edit mode
                EditItemIndex = -1;

                // Show/Hide DELETE column
                ToggleDeleteColumn(true);

                // Reject changes on the last row
                RejectChanges = true;

                // Update or insert data
                if (MustInsertRow)
                    OnInsertData(e);
                else
                    OnSaveData(e);

                // Refresh view
                OnUpdateView(EventArgs.Empty);
            }
        

            // EVENT HANDLER: DeleteCommand
            public void OnDeleteCommand(Object sender, DataGridCommandEventArgs e)
            {
                // Clear edit mode
                EditItemIndex = -1;

                // Delete data
                OnDeleteData(e);

                // First item in the row, one page back
                if (Items.Count == 1)
                    CurrentPageIndex = (CurrentPageIndex==0 ?0 :CurrentPageIndex-1);

                // Refresh view
                OnUpdateView(EventArgs.Empty);
            }
        

            // EVENT HANDLER: PageIndexChanged
            public void OnPageIndexChanged(Object sender, DataGridPageChangedEventArgs e)
            {
                // Clears edit mode
                EditItemIndex = -1;

                // Reject changes on the last row
                RejectChanges = true;
            
                // Show/Hide DELETE column
                ToggleDeleteColumn(true);

                // Set the new page index
                CurrentPageIndex = e.NewPageIndex;

                // Refresh data
                OnUpdateView(EventArgs.Empty);
            }




        
            /* ---------------------------------------------------------------------*/
            /* ------------------------  INTERNALS ---------------------------------*/
            /* ---------------------------------------------------------------------*/


            // Reject changes on the last row
            private void RejectChangesOnLastRow()
            {
                // Get the underlying DataTable object
                DataTable dt = ((DataView) DataSource).Table;
                DataRow drLast = dt.Rows[dt.Rows.Count-1];
                if (drLast.RowState == DataRowState.Added)
                    drLast.RejectChanges();
            }



            // Show/Hide the DELETE column when in edit mode
            private void ToggleDeleteColumn(bool bViewState)
            {
                int nGridColCount = Columns.Count;
                Columns[nGridColCount-1].Visible = bViewState;
            }



            // Put the grid in edit mode by adding a blank row
            private void InsertNewRow()
            {
                // Show/Hide DELETE column
                ToggleDeleteColumn(false);

                // Get the underlying DataTable object
                DataTable dt = ((DataView) DataSource).Table;
            
                // If any pending changes, stop here...
                DataTable tmpTableOfPendingChanges = dt.GetChanges(DataRowState.Added);
                if (tmpTableOfPendingChanges != null)
                    return;

                // Add the new row
                DataRow row = dt.NewRow();
                dt.Rows.Add(row);

                // Initialize the row
                DataGridInitRowEventArgs dgire = new DataGridInitRowEventArgs();
                dgire.Row = row;
                OnInitRow(dgire);

                // Goto to last page (return last index in the page)
                int nNewItemIndex = SetIndexesToLastPage(dt);

                // Turn edit mode on for the newly added row
                EditItemIndex = nNewItemIndex;
            
                // Tracks that a new row has just been added
                MustInsertRow = true;
            }



            // Update indexes to point to last page
            private int SetIndexesToLastPage(DataTable dt)
            {
                int nRemainder = (dt.Rows.Count % PageSize);
                int nNewItemIndex = nRemainder;
                CurrentPageIndex = (dt.Rows.Count / PageSize)-1;    // 0-based
                if (CurrentPageIndex <0)
                    CurrentPageIndex = 0;
                if (nNewItemIndex >0)
                    CurrentPageIndex ++;

                if (nNewItemIndex == 0)
                    nNewItemIndex = PageSize-1;
                else
                    nNewItemIndex--;

                return nNewItemIndex;
            }

            

            // Add Edit and Delete columns
            private void AddWorkerColumns()
            {
                if (ShowWebdings)
                {
                    EditColumnText = "/";
                    EditColumnUpdateText = "R";
                    EditColumnCancelText = "T";
                    DeleteColumnText = "r";
                }

                // Edit column
                EditCommandColumn editColumn = new EditCommandColumn();
                editColumn.EditText = EditColumnText;
                editColumn.UpdateText = EditColumnUpdateText;
                editColumn.CancelText = EditColumnCancelText;
                if (ShowWebdings)
                {
                    editColumn.ItemStyle.Font.Size = 11;
                    editColumn.ItemStyle.Font.Name = "wingdings 2";
                }
                Columns.Add(editColumn);


                // Delete column
                ButtonColumn deleteColumn = new ButtonColumn();
                deleteColumn.CommandName = "delete";
                deleteColumn.Text = DeleteColumnText;
                if (ShowWebdings)
                    deleteColumn.ItemStyle.Font.Name = "webdings";
                Columns.Add(deleteColumn);
            }



            // Customize items in the grid
            private void CustomizeItem(DataGridItemEventArgs e)
            {
                WebControl wc;

                // Adds a tooltip to Edit
                wc = ((WebControl) e.Item.Cells[Columns.Count-2]);
                wc.ToolTip = "Edit this row";
        
                // Adds a client-side onclick handler and a tooltip to Delete
                wc = ((WebControl) e.Item.Cells[Columns.Count-1]);
                String js = "return confirm('Do you really want to delete this row?');";
                wc.Attributes["onclick"] = js;
                wc.ToolTip = "Delete this row";
            }
        }

        public sealed class DataGridInitRowEventArgs : EventArgs
        {
            public DataRow Row;
        }
    }
}