ASP.NET-擴展gridview以允許進行過濾，排序，分頁等

Question

我在許多站點上都看到過有關擴展gridview控件的線程，因此顯然這將是重復的。 但是我還沒有找到能真正將控件擴展到您可以進行自定義排序（帶有標題圖像），通過在標題列中放置下拉列表或文本框（逐列）進行過濾以及自定義分頁（一個）的控件不會返回所有記錄，而只會返回給定頁面請求的記錄）。

有沒有很好的教程來演示gridview的內部工作原理以及如何覆蓋適當的功能？ 我在這里和那里已經看到了幾段代碼，但似乎都沒有真正起作用，並且不能很好地解釋事情。

任何鏈接將不勝感激。 謝謝！

Answer 1

我自己擴展了GridView控件，以允許對圖像進行排序，自定義分頁（因此您可以從下拉列表中選擇每頁多少條記錄）以及其他一些功能。 但是，您將無法執行僅返回所請求頁面的記錄的自定義分頁，因為這是您的數據源需要處理的，而不是GridView。

我真正能做的就是給您一些代碼，希望對您有所幫助。 這是很舊的代碼（C＃3.0之前的版本），但可能有一些用處：

首先，這是擴展標准GridView的自定義GridView控件：

using System;
using System.Collections;
using System.Drawing;
using System.Web.UI.WebControls;
using Diplo.WebControls.DataControls.PagerTemplates;
using Image=System.Web.UI.WebControls.Image;

namespace Diplo.WebControls.DataControls
{
    /// <summary>
    /// Extended <see cref="GridView"/> with some additional cool properties
    /// </summary>
    public class DiploGridView : GridView
    {
        #region Properties

        /// <summary>
        /// Gets or sets a value indicating whether a sort graphic is shown in column headings
        /// </summary>
        /// <value><c>true</c> if sort graphic is displayed; otherwise, <c>false</c>.</value>
        public bool EnableSortGraphic
        {
            get
            {
                object o = ViewState["EnableSortGraphic"];
                if (o != null)
                {
                    return (bool)o;
                }
                return true;
            }
            set
            {
                ViewState["EnableSortGraphic"] = value;
            }
        }

        /// <summary>
        /// Gets or sets the sort ascending image when <see cref="EnableSortGraphic"/> is <c>true</c>
        /// </summary>
        public string SortAscendingImage
        {
            get
            {
                object o = ViewState["SortAscendingImage"];
                if (o != null)
                {
                    return (string)o;
                }
                return Page.ClientScript.GetWebResourceUrl(GetType(), SharedWebResources.ArrowUpImage);
            }
            set
            {
                ViewState["SortAscendingImage"] = value;
            }
        }

        /// <summary>
        /// Gets or sets the sort descending image <see cref="EnableSortGraphic"/> is <c>true</c>
        /// </summary>
        public string SortDescendingImage
        {
            get
            {
                object o = ViewState["SortDescendingImage"];
                if (o != null)
                {
                    return (string)o;
                }
                return Page.ClientScript.GetWebResourceUrl(GetType(), SharedWebResources.ArrowDownImage);
            }
            set
            {
                ViewState["SortDescendingImage"] = value;
            }
        }

        /// <summary>
        /// Gets or sets the custom pager settings mode.
        /// </summary>
        public CustomPagerMode CustomPagerSettingsMode
        {
            get
            {
                object o = ViewState["CustomPagerSettingsMode"];
                if (o != null)
                {
                    return (CustomPagerMode)o;
                }
                return CustomPagerMode.None;
            }
            set
            {
                ViewState["CustomPagerSettingsMode"] = value;
            }
        }

        /// <summary>
        /// Gets or sets a value indicating whether the columns in the grid can be re-sized in the UI
        /// </summary>
        /// <value><c>true</c> if  column resizing is allowed; otherwise, <c>false</c>.</value>
        public bool AllowColumnResizing
        {
            get
            {
                object o = ViewState["AllowColumnResizing"];
                if (o != null)
                {
                    return (bool)o;
                }
                return false;
            }
            set
            {
                ViewState["AllowColumnResizing"] = value;
            }
        }

        /// <summary>
        /// Gets or sets the highlight colour for the row
        /// </summary>
        public Color RowStyleHighlightColour
        {
            get
            {
                object o = ViewState["RowStyleHighlightColour"];
                if (o != null)
                {
                    return (Color)o;
                }
                return Color.Empty;
            }
            set
            {
                ViewState["RowStyleHighlightColour"] = value;
            }
        }

        #endregion Properties

        #region Enums

        /// <summary>
        /// Represents additional custom paging modes
        /// </summary>
        public enum CustomPagerMode
        {
            /// <summary>
            /// No custom paging mode
            /// </summary>
            None,
            /// <summary>
            /// Shows the rows drop-down list <i>and</i> the previous and next buttons
            /// </summary>
            RowsPagePreviousNext,
            /// <summary>
            /// Only shows the previous and next buttons
            /// </summary>
            PagePreviousNext
        }

        #endregion

        #region Overridden Events

        /// <summary>
        /// Initializes the pager row displayed when the paging feature is enabled.
        /// </summary>
        /// <param name="row">A <see cref="T:System.Web.UI.WebControls.GridViewRow"></see> that represents the pager row to initialize.</param>
        /// <param name="columnSpan">The number of columns the pager row should span.</param>
        /// <param name="pagedDataSource">A <see cref="T:System.Web.UI.WebControls.PagedDataSource"></see> that represents the data source.</param>
        protected override void InitializePager(GridViewRow row, int columnSpan, PagedDataSource pagedDataSource)
        {
            switch (CustomPagerSettingsMode)
            {
                case CustomPagerMode.RowsPagePreviousNext:
                    PagerTemplate = new RowsPagePreviousNext(pagedDataSource, this);
                    break;
                case CustomPagerMode.PagePreviousNext:
                    PagerTemplate = new PagePreviousNext(pagedDataSource, this);
                    break;
                case CustomPagerMode.None:
                    break;
                default:
                    break;
            }

            base.InitializePager(row, columnSpan, pagedDataSource);
        }

        /// <summary>
        /// Raises the <see cref="E:System.Web.UI.Control.PreRender"></see> event.
        /// </summary>
        /// <param name="e">An <see cref="T:System.EventArgs"></see> that contains the event data.</param>
        protected override void OnPreRender(EventArgs e)
        {
            if (AllowColumnResizing && Visible)
            {
                string vars = String.Format("var _DiploGridviewId = '{0}';\n", ClientID);

                if (!Page.ClientScript.IsClientScriptBlockRegistered("Diplo_GridViewVars"))
                {
                    Page.ClientScript.RegisterClientScriptBlock(GetType(), "Diplo_GridViewVars", vars, true);
                }

                Page.ClientScript.RegisterClientScriptInclude("Diplo_GridView.js",
                                                              Page.ClientScript.GetWebResourceUrl(GetType(), "Diplo.WebControls.SharedWebResources.Diplo_GridView_Resize.js"));
            }

            base.OnPreRender(e);
        }

        /// <summary>
        /// Raises the <see cref="E:System.Web.UI.WebControls.GridView.RowCreated"></see> event.
        /// </summary>
        /// <param name="e">A <see cref="T:System.Web.UI.WebControls.GridViewRowEventArgs"></see> that contains event data.</param>
        protected override void OnRowCreated(GridViewRowEventArgs e)
        {
            if (EnableSortGraphic)
            {
                if (!((e.Row == null)) && e.Row.RowType == DataControlRowType.Header)
                {
                    foreach (TableCell cell in e.Row.Cells)
                    {
                        if (cell.HasControls())
                        {
                            LinkButton button = ((LinkButton)(cell.Controls[0]));
                            if (!((button == null)))
                            {
                                Image image = new Image();
                                image.ImageUrl = "images/default.gif";
                                image.ImageAlign = ImageAlign.Baseline;
                                if (SortExpression == button.CommandArgument)
                                {
                                    image.ImageUrl = SortDirection == SortDirection.Ascending ? SortAscendingImage : SortDescendingImage;
                                    Literal space = new Literal();
                                    space.Text = "&nbsp;";
                                    cell.Controls.Add(space);
                                    cell.Controls.Add(image);
                                }
                            }
                        }
                    }
                }
            }

            if (RowStyleHighlightColour != Color.Empty)
            {
                if (e.Row != null)
                {
                    if (e.Row.RowType == DataControlRowType.DataRow)
                    {
                        e.Row.Attributes.Add("onmouseover", String.Format("this.style.backgroundColor='{0}'", ColorTranslator.ToHtml(RowStyleHighlightColour)));
                        e.Row.Attributes.Add("onmouseout", "this.style.backgroundColor=''");
                    }
                }
            }

            base.OnRowCreated(e);
        }

        /// <summary>
        /// Creates the control hierarchy that is used to render a composite data-bound control based on the values that are stored in view state.
        /// </summary>
        protected override void CreateChildControls()
        {
            base.CreateChildControls();

            CheckShowPager();
        }

        private void CheckShowPager()
        {
            if (CustomPagerSettingsMode != CustomPagerMode.None && AllowPaging)
            {
                if (TopPagerRow != null)
                {
                    TopPagerRow.Visible = true;
                }

                if (BottomPagerRow != null)
                {
                    BottomPagerRow.Visible = true;
                }
            }
        }

        /// <summary>
        /// Creates the control hierarchy used to render the <see cref="T:System.Web.UI.WebControls.GridView"></see> control using the specified data source.
        /// </summary>
        /// <param name="dataSource">An <see cref="T:System.Collections.IEnumerable"></see> that contains the data source for the <see cref="T:System.Web.UI.WebControls.GridView"></see> control.</param>
        /// <param name="dataBinding">true to indicate that the child controls are bound to data; otherwise, false.</param>
        /// <returns>The number of rows created.</returns>
        protected override int CreateChildControls(IEnumerable dataSource, bool dataBinding)
        {
            int i = base.CreateChildControls(dataSource, dataBinding);

            CheckShowPager();

            return i;
        }

    #endregion Overridden Events
}
}

然后有一個用作頁面模板的自定義頁面類：

using System;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
using System.Web.UI;

namespace Diplo.WebControls.DataControls.PagerTemplates
{
    /// <summary>
    /// Paging template for the <see cref="DiploGridView"/>
    /// </summary>
    public class RowsPagePreviousNext : ITemplate
    {
        readonly PagedDataSource _pagedDataSource;
        readonly DiploGridView DiploGridView;

        /// <summary>
        /// Initializes a new instance of the <see cref="RowsPagePreviousNext"/> class.
        /// </summary>
        /// <param name="pagedDataSource">The <see cref="PagedDataSource"/>.</param>
        /// <param name="DiploGrid">A reference to the <see cref="DiploGridView"/>.</param>
        public RowsPagePreviousNext(PagedDataSource pagedDataSource, DiploGridView DiploGrid)
        {
            _pagedDataSource = pagedDataSource;
            DiploGridView = DiploGrid;
        }

        /// <summary>
        /// When implemented by a class, defines the <see cref="T:System.Web.UI.Control"></see> object that child controls and templates belong to. These child controls are in turn defined within an inline template.
        /// </summary>
        /// <param name="container">The <see cref="T:System.Web.UI.Control"></see> object to contain the instances of controls from the inline template.</param>
        void ITemplate.InstantiateIn(Control container)
        {
            Literal space = new Literal();
            space.Text = "&nbsp;";

            HtmlGenericControl divLeft = new HtmlGenericControl("div");
            divLeft.Style.Add("float", "left");
            divLeft.Style.Add(HtmlTextWriterStyle.Width, "25%");

            Label lb = new Label();
            lb.Text = "Show rows: ";
            divLeft.Controls.Add(lb);

            DropDownList ddlPageSize = new DropDownList();
            ListItem item;
            ddlPageSize.AutoPostBack = true;
            ddlPageSize.ToolTip = "Select number of rows per page";

            int max = (_pagedDataSource.DataSourceCount < 50) ? _pagedDataSource.DataSourceCount : 50;
            int i;
            const int increment = 5;
            bool alreadySelected = false;
            for (i = increment; i <= max; i = i + increment)
            {
                item = new ListItem(i.ToString());
                if (i == _pagedDataSource.PageSize)
                {
                    item.Selected = true;
                    alreadySelected = true;
                }
                ddlPageSize.Items.Add(item);
            }

            item = new ListItem("All", _pagedDataSource.DataSourceCount.ToString());
            if (_pagedDataSource.DataSourceCount == _pagedDataSource.PageSize && alreadySelected == false)
            {
                item.Selected = true;
                alreadySelected = true;
            }

            if (_pagedDataSource.DataSourceCount > (i - increment) && alreadySelected == false)
            {
                item.Selected = true;
            }

            ddlPageSize.Items.Add(item);

            ddlPageSize.SelectedIndexChanged += new EventHandler(ddlPageSize_SelectedIndexChanged);

            divLeft.Controls.Add(ddlPageSize);

            HtmlGenericControl divRight = new HtmlGenericControl("div");
            divRight.Style.Add("float", "right");
            divRight.Style.Add(HtmlTextWriterStyle.Width, "75%");
            divRight.Style.Add(HtmlTextWriterStyle.TextAlign, "right");

            Literal lit = new Literal();
            lit.Text = String.Format("Found {0} record{1}. Page ", 
                _pagedDataSource.DataSourceCount, 
                (_pagedDataSource.DataSourceCount == 1) ? String.Empty : "s" );
            divRight.Controls.Add(lit);

            TextBox tbPage = new TextBox();
            tbPage.ToolTip = "Enter page number";
            tbPage.Columns = 2;
            tbPage.MaxLength = 3;
            tbPage.Text = (_pagedDataSource.CurrentPageIndex + 1).ToString();
            tbPage.CssClass = "pagerTextBox";
            tbPage.AutoPostBack = true;
            tbPage.TextChanged += new EventHandler(tbPage_TextChanged);
            divRight.Controls.Add(tbPage);
            if (_pagedDataSource.PageCount < 2)
                tbPage.Enabled = false;

            lit = new Literal();
            lit.Text = " of " + _pagedDataSource.PageCount;
            divRight.Controls.Add(lit);

            divRight.Controls.Add(space);

            Button btn = new Button();
            btn.Text = "";
            btn.CommandName = "Page";
            btn.CommandArgument = "Prev";
            btn.SkinID = "none";
            btn.Enabled = !_pagedDataSource.IsFirstPage;
            btn.CssClass = (btn.Enabled) ? "buttonPreviousPage" : "buttonPreviousPageDisabled";
            if (btn.Enabled)
                btn.ToolTip = "Previous page";
            divRight.Controls.Add(btn);

            btn = new Button();
            btn.Text = "";
            btn.CommandName = "Page";
            btn.CommandArgument = "Next";
            btn.SkinID = "none";
            btn.CssClass = "buttonNext";
            btn.Enabled = !_pagedDataSource.IsLastPage;
            btn.CssClass = (btn.Enabled) ? "buttonNextPage" : "buttonNextPageDisabled";
            if (btn.Enabled)
                btn.ToolTip = "Next page";
            divRight.Controls.Add(btn);

            container.Controls.Add(divLeft);
            container.Controls.Add(divRight);
        }

        /// <summary>
        /// Handles the TextChanged event of the tbPage control.
        /// </summary>
        /// <param name="sender">The source of the event.</param>
        /// <param name="e">The <see cref="System.EventArgs"/> instance containing the event data.</param>
        void tbPage_TextChanged(object sender, EventArgs e)
        {
            TextBox tb = sender as TextBox;

            if (tb != null)
            {
                int page;
                if (int.TryParse(tb.Text, out page))
                {
                    if (page <= _pagedDataSource.PageCount && page > 0)
                    {
                        DiploGridView.PageIndex = page - 1;
                    }
                }
            }
        }

        /// <summary>
        /// Handles the SelectedIndexChanged event of the ddlPageSize control.
        /// </summary>
        /// <param name="sender">The source of the event.</param>
        /// <param name="e">The <see cref="System.EventArgs"/> instance containing the event data.</param>
        void ddlPageSize_SelectedIndexChanged(object sender, EventArgs e)
        {
            DropDownList list = sender as DropDownList;
            if (list != null) DiploGridView.PageSize = Convert.ToInt32(list.SelectedValue);
        }
    }
}

由於服務器控件很復雜，我無法真正通過它來與您交流，我只是希望它能為您提供幫助。