使用DataPager扩展asp：Repeater时出现问题

Question

I'm extending asp:Repeater to use DataPager, and now my code work with SqlDataSource. To get better performance, I want to use ObjectDataSource with it, but I have to use QueryStringField of DataPager, otherwise I have to click page number twice to make it work. Can any one help on this? this is my code:

namespace WebTest.UserControl
{
    public class PageableRepeater : Repeater, IPageableItemContainer
    {
        private static readonly object EventTotalRowCountAvailable = new object();

        private int _startRowIndex = 0;
        private int _maximumRows = -1;
        private int _totalRowCount = -1;

        protected override void OnInit(EventArgs e)
        {
            base.OnInit(e);
            Page.RegisterRequiresControlState(this);
        }

        protected override void LoadControlState(object savedState)
        {
            _startRowIndex = 0;
            _maximumRows = -1;
            _totalRowCount = -1;
            object[] state = savedState as object[];

            if (state != null)
            {
                base.LoadControlState(state[0]);

                if (state[1] != null)
                {
                    _totalRowCount = (int)state[1];
                }

            }
            else
            {
                base.LoadControlState(null);
            }
            if (!IsViewStateEnabled)
            {
                OnTotalRowCountAvailable(new PageEventArgs(_startRowIndex, _maximumRows, _totalRowCount));
            }
        }

        protected override object SaveControlState()
        {
            object baseState = base.SaveControlState();
            if (baseState != null || _totalRowCount != -1)
            {
                object[] state = new object[2];
                state[0] = baseState;
                state[1] = _totalRowCount;
                return state;
            }
            return true;
        }

        protected override System.Collections.IEnumerable GetData()
        {
            ListViewPagedDataSource pagedDataSource = new ListViewPagedDataSource();
            pagedDataSource.StartRowIndex = _startRowIndex;
            pagedDataSource.MaximumRows = _maximumRows;
            if (DataSource is ObjectDataSource)
            {
                SelectArguments.StartRowIndex = _startRowIndex;
                SelectArguments.MaximumRows = _maximumRows;
                SelectArguments.RetrieveTotalRowCount = true;

                pagedDataSource.DataSource = base.GetData();
                _totalRowCount = SelectArguments.TotalRowCount;
                pagedDataSource.AllowServerPaging = true;
                pagedDataSource.TotalRowCount = _totalRowCount;
            }
            else
            {
                pagedDataSource.DataSource = base.GetData();
                pagedDataSource.AllowServerPaging = false;
                pagedDataSource.TotalRowCount = 0;
                _totalRowCount = pagedDataSource.DataSourceCount;
            }
            return pagedDataSource;
        }

        protected override void CreateControlHierarchy(bool useDataSource)
        {
            base.CreateControlHierarchy(useDataSource);
            OnTotalRowCountAvailable(new PageEventArgs(_startRowIndex, _maximumRows, _totalRowCount));
        }

        private void OnTotalRowCountAvailable(PageEventArgs pageEventArgs)
        {
            EventHandler<PageEventArgs> handler = (EventHandler<PageEventArgs>)Events[EventTotalRowCountAvailable];
            if (handler != null)
            {
                handler(this, pageEventArgs);
            }
        }

        public int MaximumRows
        {
            get { return _maximumRows; }
        }

        public int StartRowIndex
        {
            get { return _startRowIndex; }
        }

        public void SetPageProperties(int startRowIndex, int maximumRows, bool databind)
        {
            if (maximumRows < 1)
            {
                throw new ArgumentOutOfRangeException("maximumRows");
            }
            if (startRowIndex < 0)
            {
                throw new ArgumentOutOfRangeException("startRowIndex");
            }

            _startRowIndex = startRowIndex;
            _maximumRows = maximumRows;

            if (databind)
            {
                RequiresDataBinding = true;
            }
        }

        public event EventHandler<PageEventArgs> TotalRowCountAvailable
        {
            add
            {
                Events.AddHandler(EventTotalRowCountAvailable, value);
            }
            remove
            {
                Events.RemoveHandler(EventTotalRowCountAvailable, value);
            }
        }
    }
}

By the way, I found another implementation to this on CodeProject , but I don't think it use IPageableItemContainer very well.

Answer 1

I know this is an old one, but I've recently been looking for a solution to using the Repeater with a DataPager control.

Most research takes me to this CodeProject article , but it seems like a bit of a hack to me. I've worked on this problem a bit, and put it to the side for a while as I was spinning my wheels on it, until I saw your question and sample code. I was able to take your code and apply it to mine to get a working solution (at least it works for me). With the DataPagerRepeater control below, I'm able to drop the DataPagerRepeater, DataPager, and a DataSource (ObjectDataSource, etc) on the page. Set the DataPagerRepeaters DataSource or DataSourceID to point to the data source, then set the DataPagers PagedControlID to the DataPagerRepeater. Seems to work great.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace My.Web.UI.WebControls
{
    /// <summary>
    /// Extends the Repeater to be compatable with a DataPager
    /// </summary>
    /// <remarks>
    /// To page through data in a control that implements the IPageableItemContainer interface, DataPager control can be used. 
    /// Repeater does not support paging and does not implement IPageableItemContainer interface. ListView is the only control that works with DataPager. 
    /// 
    /// The DataPager control supports built-in paging user interface (UI). NumericPagerField object enables users to select a page of data by page number.
    /// NextPreviousPagerField object enables users to move through pages of data one page at a time, or to jump to the first or last page of data. 
    /// The size of the pages of data is set by using the PageSize property of the DataPager control. One or more pager field objects can be used in 
    /// a single DataPager control. Custom paging UI can be created by using the TemplatePagerField object. In the TemplatePagerField template, 
    /// the DataPager control is referenced by using the Container property which provides access to the properties of the DataPager control. 
    /// These properties include the starting row index, the page size, and the total number of rows currently bound to the control. 
    /// </remarks>
    [ToolboxData("<my:DataPagerRepeater runat=server></my:DataPagerRepeater>")]
    [Themeable(true)]
    public class DataPagerRepeater : Repeater, IPageableItemContainer
    {
        /// <summary>Gets the maximum number of items to display on a single page of the <see cref="T:InteriorHealth.Web.UI.WebControls.DataPagerRepeater" /> control.
        /// </summary>
        /// <returns>The maximum number of items to display on a single page of the <see cref="T:InteriorHealth.Web.UI.WebControls.DataPagerRepeater" /> control. 
        /// </returns>
        public int MaximumRows
        {
            get;
            //{
            //    return ViewState["maxrows"] != null ? (int)ViewState["maxrows"] : -1;
            //}
            private set;
            //{
            //    ViewState["maxrows"] = value;
            //}
        }

        /// <summary>Gets the index of the first record that is displayed on a page of data in the <see cref="T:InteriorHealth.Web.UI.WebControls.DataPagerRepeater" /> control.
        /// </summary>
        /// <returns>The index of the first record that is displayed on a page of data in the <see cref="T:InteriorHealth.Web.UI.WebControls.DataPagerRepeater" /> control.
        /// </returns>
        public int StartRowIndex
        {
            get;
            //{
            //    return ViewState["startrowindex"] != null ? (int)ViewState["startrowindex"] : -1;
            //}
            private set;
            //{
            //    ViewState["startrowindex"] = value;
            //}
        }

        /// <summary>
        /// Total number of rows that are avialable, regardless of what is currently being displayed
        /// </summary>
        private int TotalRowsAvailable
        {
            get;
            //{
            //    return ViewState["totalrows"] != null ? (int)ViewState["totalrows"] : -1;
            //}
            set;
            //{
            //    ViewState["totalrows"] = value;
            //}
        }

        private static readonly object EventPagePropertiesChanged = new object();
        /// <summary>Occurs when the page properties change, after the <see cref="T:InteriorHealth.Web.UI.WebControls.DataPagerRepeater" /> control sets the new values.
        /// </summary>
        public event EventHandler PagePropertiesChanged
        {
            add
            {
                base.Events.AddHandler(DataPagerRepeater.EventPagePropertiesChanged, value);
            }
            remove
            {
                base.Events.RemoveHandler(DataPagerRepeater.EventPagePropertiesChanged, value);
            }
        }

        private static readonly object EventPagePropertiesChanging = new object();
        /// <summary>Occurs when the page properties change, but before the <see cref="T:InteriorHealth.Web.UI.WebControls.DataPagerRepeater" /> control sets the new values.
        /// </summary>
        public event EventHandler<PagePropertiesChangingEventArgs> PagePropertiesChanging
        {
            add
            {
                base.Events.AddHandler(DataPagerRepeater.EventPagePropertiesChanging, value);
            }
            remove
            {
                base.Events.RemoveHandler(DataPagerRepeater.EventPagePropertiesChanging, value);
            }
        }

        private static readonly object EventTotalRowCountAvailable = new object();
        /// <summary>For a description of this member, see <see cref="E:System.Web.UI.WebControls.IPageableItemContainer.TotalRowCountAvailable" />.
        /// </summary>
        public event EventHandler<PageEventArgs> TotalRowCountAvailable
        {
            add
            {
                base.Events.AddHandler(DataPagerRepeater.EventTotalRowCountAvailable, value);
            }
            remove
            {
                base.Events.RemoveHandler(DataPagerRepeater.EventTotalRowCountAvailable, value);
            }
        }

        /// <summary>
        /// Register the control as one who's control state needs to be persisted
        /// </summary>
        /// <param name="e"></param>
        protected override void OnInit(EventArgs e)
        {
            base.OnInit(e);
            Page.RegisterRequiresControlState(this);
        }

        /// <summary>
        /// Initialize the start row index, maximum rows, and total rows available values.  Load the total rows available from viewstate.
        /// </summary>
        /// <param name="savedState"></param>
        protected override void LoadControlState(object savedState)
        {
            this.StartRowIndex = 0;
            this.MaximumRows = -1;
            this.TotalRowsAvailable = -1;
            object[] state = savedState as object[];

            if (state != null)
            {
                base.LoadControlState(state[0]);

                if (state[1] != null)
                {
                    this.TotalRowsAvailable = (int)state[1];
                }

            }
            else
            {
                base.LoadControlState(null);
            }

            if (!IsViewStateEnabled)
            {
                OnTotalRowCountAvailable(new PageEventArgs(this.StartRowIndex, this.MaximumRows, this.TotalRowsAvailable));
            }
        }

        /// <summary>
        /// Save the total rows available value to viewstate
        /// </summary>
        /// <returns></returns>
        protected override object SaveControlState()
        {
            object baseState = base.SaveControlState();
            if (baseState != null || this.TotalRowsAvailable != -1)
            {
                object[] state = new object[2];
                state[0] = baseState;
                state[1] = this.TotalRowsAvailable;
                return state;
            }
            return true;
        }


        /// <summary>Sets the properties of a page of data in the <see cref="T:InteriorHealth.Web.UI.WebControls.DataPagerRepeater" /> control.
        /// </summary>
        /// <param name="startRowIndex">The index of the first record on the page.</param>
        /// <param name="maximumRows">The maximum number of items on a single page.</param>
        /// <param name="databind">true to rebind the control after the properties are set; otherwise, false.</param>
        /// <exception cref="T:System.ArgumentOutOfRangeException">
        ///   <paramref name="maximumRows" /> is less than 1.-or-<paramref name="startRowIndex" /> is less than 0.
        ///   </exception>
        public void SetPageProperties(int startRowIndex, int maximumRows, bool databind)
        {
            if (maximumRows < 1)
            {
                throw new ArgumentOutOfRangeException("maximumRows");
            }
            if (startRowIndex < 0)
            {
                throw new ArgumentOutOfRangeException("startRowIndex");
            }
            if (this.StartRowIndex != startRowIndex || this.StartRowIndex != maximumRows)
            {
                PagePropertiesChangingEventArgs pagePropertiesChangingEventArgs = new PagePropertiesChangingEventArgs(startRowIndex, maximumRows);
                if (databind)
                {
                    this.OnPagePropertiesChanging(pagePropertiesChangingEventArgs);
                }

                this.StartRowIndex = pagePropertiesChangingEventArgs.StartRowIndex;
                this.MaximumRows = pagePropertiesChangingEventArgs.MaximumRows;

                if (databind)
                {
                    this.OnPagePropertiesChanged(EventArgs.Empty);
                }
            }
            if (databind)
            {
                this.RequiresDataBinding = true;
            }

            //this.OnTotalRowCountAvailable(new PageEventArgs(this.StartRowIndex, this.MaximumRows, this.TotalRowsAvailable));
        }


        /// <summary>
        /// Creates a control hierarchy, with or without the specified data source.
        /// </summary>
        /// <param name="useDataSource">
        /// Indicates whether to use the specified data source. 
        /// </param>
        protected override void CreateControlHierarchy(bool useDataSource)
        {
            base.CreateControlHierarchy(useDataSource);
            OnTotalRowCountAvailable(new PageEventArgs(this.StartRowIndex, this.MaximumRows, this.TotalRowsAvailable));
        }

        /// <summary>Returns an <see cref="T:System.Collections.IEnumerable" /> interface from the data source.</summary>
        /// <returns>An object implementing <see cref="T:System.Collections.IEnumerable" /> that represents the data from the data source.</returns>
        protected override System.Collections.IEnumerable GetData()
        {
            System.Collections.IEnumerable data = base.GetData();
            this.TotalRowsAvailable = this.SelectArguments.TotalRowCount;

            this.OnTotalRowCountAvailable(new PageEventArgs(this.StartRowIndex, this.MaximumRows, this.TotalRowsAvailable));
            return data;
        }

        /// <summary>Raises the <see cref="E:InteriorHealth.Web.UI.WebControls.DataPagerRepeater.PagePropertiesChanging" /> event.
        /// </summary>
        /// <param name="e">The event data.</param>
        protected virtual void OnPagePropertiesChanging(PagePropertiesChangingEventArgs e)
        {
            EventHandler<PagePropertiesChangingEventArgs> eventHandler = (EventHandler<PagePropertiesChangingEventArgs>)base.Events[DataPagerRepeater.EventPagePropertiesChanging];
            if (eventHandler != null)
            {
                eventHandler(this, e);
            }
        }

        /// <summary>Raises the <see cref="E:InteriorHealth.Web.UI.WebControls.DataPagerRepeater.SelectedIndexChanged" /> event.</summary>
        /// <param name="e">The event data.</param>
        protected virtual void OnPagePropertiesChanged(EventArgs e)
        {
            EventHandler eventHandler = (EventHandler)base.Events[DataPagerRepeater.EventPagePropertiesChanged];
            if (eventHandler != null)
            {
                eventHandler(this, e);
            }
        } 

        /// <summary>Raises the <see cref="E:InteriorHealth.Web.UI.WebControls.DataPagerRepeater.PagePropertiesChanging" /> event.</summary>
        /// <param name="e">The event data.</param>
        protected virtual void OnTotalRowCountAvailable(PageEventArgs e)
        {
            EventHandler<PageEventArgs> eventHandler = (EventHandler<PageEventArgs>)base.Events[DataPagerRepeater.EventTotalRowCountAvailable];
            if (eventHandler != null)
            {
                eventHandler(this, e);
            }
        }


        /// <summary>
        /// Override the selection of rows that we need
        /// </summary>
        /// <returns></returns>
        protected override DataSourceSelectArguments CreateDataSourceSelectArguments()
        {
            DataSourceSelectArguments arg = base.CreateDataSourceSelectArguments();
            arg.StartRowIndex = this.StartRowIndex;
            arg.MaximumRows = this.MaximumRows;

            return arg;
        }
    }
}