DataGrid 模板列,实现多选，全选复选框

于 2005-01-11 17:28:00 发布
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分类专栏： asp.net 文章标签： datagrid null properties server assembly string
版权声明：本文为博主原创文章，遵循 CC 4.0 BY-SA 版权协议，转载请附上原文出处链接和本声明。
本文链接：https://blog.youkuaiyun.com/wsyl_czl/article/details/248976
该博客主要围绕DataGrid中的RowSelectorColumn展开，介绍了其创建、查找方法，还给出了使用示例。同时，对RowSelectorColumn中的ParticipantRadioButton类进行了详细说明，包括其数据加载、事件处理及属性渲染等方面的实现。

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using System;
using System.Collections;
using System.Collections.Specialized;
using System.ComponentModel;
using System.Resources;
using System.Web;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;

namespace MetaBuilders.WebControls {

    /// <summary>
    /// A <see cref="DataGridColumn"/> which shows a checkbox in each row to signal the selection of that row.
    /// </summary>
    /// <example>
    /// This example shows the use of this column in a simple <see cref="DataGrid"/>
    /// <code>
    /// <![CDATA[
    /// <%@ Import Namespace="System.Data" %>
    /// <%@ Register TagPrefix="mbrsc" Namespace="MetaBuilders.WebControls" Assembly="MetaBuilders.WebControls.RowSelectorColumn" %>
    /// 
    /// <html>
    ///    <script language="C#" runat="server">
    ///  
    ///       ICollection CreateDataSource() 
    ///       {
    ///          DataTable dt = new DataTable();
    ///          DataRow dr;
    ///  
    ///          dt.Columns.Add(new DataColumn("IntegerValue", typeof(Int32)));
    ///          dt.Columns.Add(new DataColumn("StringValue", typeof(string)));
    ///  
    ///          for (int i = 0; i < 5; i++) 
    ///          {
    ///             dr = dt.NewRow();
    ///  
    ///             dr[0] = i;
    ///             dr[1] = "Item " + i.ToString();
    ///  
    ///             dt.Rows.Add(dr);
    ///          }
    ///  
    ///          DataView dv = new DataView(dt);
    ///          return dv;
    ///       }
    ///  
    ///       void Page_Load(Object sender, EventArgs e) 
    ///       {
    ///  
    ///          if (!IsPostBack) 
    ///          {
    ///             // Load this data only once.
    ///             ItemsGrid.DataSource= CreateDataSource();
    ///             ItemsGrid.DataBind();
    ///          }
    ///       }
    ///       
    ///       protected void ShowSelections( Object sender, EventArgs e ) {
    ///         RowSelectorColumn rsc = ItemsGrid.Columns[0] as RowSelectorColumn;
    ///         Message.Text = "Total selected rows = " + rsc.SelectedIndexes.Length.ToString() + "<br>";
    ///         foreach( Int32 selectedIndex in rsc.SelectedIndexes ) {
    ///             Message.Text += selectedIndex.ToString() + "<br>";
    ///         }
    ///       }
    ///  
    ///    </script>
    ///  
    /// <body>
    ///  
    ///    <form runat=server>
    ///  
    ///       <h3>DataGrid Example</h3>
    ///  
    ///       <asp:DataGrid id="ItemsGrid"
    ///            BorderColor="black"
    ///            BorderWidth="1"
    ///            CellPadding="3"
    ///            AutoGenerateColumns="true"
    ///            runat="server">
    /// 
    ///          <HeaderStyle BackColor="darkblue" forecolor="white">
    ///          </HeaderStyle> 
    ///          <Columns>
    ///             <mbrsc:RowSelectorColumn allowselectall="true" />
    ///          </Columns>
    ///  
    ///       </asp:DataGrid>
    ///       
    ///       <asp:Button runat="server" onclick="ShowSelections" text="Show Selections" />
    ///       <br>
    ///       <asp:Label runat="server" id="Message" />
    ///  
    ///    </form>
    ///  
    /// </body>
    /// </html>
    /// ]]>
    /// </code>
    /// </example>
    public class RowSelectorColumn : DataGridColumn {

        #region Constructors
        
        /// <summary>
        /// Creates a new instance of the RowSelectorColumn control.
        /// </summary>
        [Description("Creates a new instance of the RowSelectorColumn control.")]
        public RowSelectorColumn() : base() {
        }
        #endregion
        
        #region FindColumns
        /// <summary>
        /// Finds the first <see cref="RowSelectorColumn"/> in the given <see cref="DataGrid"/>.
        /// </summary>
        /// <param name="grid">The <see cref="DataGrid"/> to search.</param>
        /// <returns>The <see cref="RowSelectorColumn"/> found, or null.</returns>
        public static RowSelectorColumn FindColumn( DataGrid grid ) {
            RowSelectorColumn foundCol = null;
            foreach( DataGridColumn col in grid.Columns ) {
                foundCol = col as RowSelectorColumn;
                if ( foundCol != null  ) {
                    return foundCol;
                }
            }
            return null;
        }
        
        /// <summary>
        /// Finds the first <see cref="RowSelectorColumn"/> in the given <see cref="DataGrid"/> after or at the given column index.
        /// </summary>
        /// <param name="grid">The <see cref="DataGrid"/> to search.</param>
        /// <param name="startIndex">The index of the column to start the search.</param>
        /// <returns>The <see cref="RowSelectorColumn"/> found, or null.</returns>
        public static RowSelectorColumn FindColumn( DataGrid grid, Int32 startIndex ) {
            RowSelectorColumn foundCol = null;
            for( Int32 i = startIndex; i < grid.Columns.Count; i++ ) {
                foundCol = grid.Columns[i] as RowSelectorColumn;
                if ( foundCol != null  ) {
                    return foundCol;
                }
            }
            return null;
        }

        #endregion

        #region Cell Creation
        /// <summary>
        /// This member overrides <see cref="DataGridColumn.InitializeCell"/>.
        /// </summary>
        public override void InitializeCell(TableCell cell, int columnIndex, ListItemType itemType) {
            base.InitializeCell(cell, columnIndex, itemType);

            switch (itemType) {
                case ListItemType.EditItem:
                case ListItemType.Item:
                case ListItemType.AlternatingItem:
                case ListItemType.SelectedItem:

                    if ( this.SelectionMode == ListSelectionMode.Multiple ) {
                        ParticipantCheckBox selector = new ParticipantCheckBox();
                        selector.ID = "RowSelectorColumnSelector";
                        cell.Controls.Add( selector );
                        if ( AllowSelectAll ) {
                            RegisterForSelectAll( selector );
                        }
                    } else {
                        ParticipantRadioButton selector = new ParticipantRadioButton();
                        selector.Name = "RowSelectorColumnSelector";
                        selector.ID = "RowSelectorColumnSelector";
                        cell.Controls.Add( selector );
                        selector.DataBinding += new EventHandler( this.selectorDataBinding );
                    }
                    break;
                case ListItemType.Header:
                    if ( AllowSelectAll && this.SelectionMode == ListSelectionMode.Multiple ) {
                        selectAllControl = new System.Web.UI.HtmlControls.HtmlInputCheckBox();
                        selectAllControl.ID = "RowSelectorColumnAllSelector";
                        ApplyScriptToSelectAllCheckBox();
                        RegisterSelectAllScript();
                        cell.Controls.Add( selectAllControl );
                    }
                    break;
            }
            
        }

        
        /// <summary>
        /// 
        /// </summary>
        protected virtual void SetIndexValue( HtmlInputRadioButton radioSelector ) {
            DataGridItem row = radioSelector.NamingContainer as DataGridItem;
            if ( row != null ) {
                radioSelector.Value = row.ItemIndex.ToString();
            }
        }


        /// <summary>
        /// Gets the checkbox appearing in the header row which controls the other checkboxes.
        /// </summary>
        /// <remarks>The checkbox if <see cref="AllowSelectAll"/> is true, otherwise null.</remarks>
        [Description("Gets the checkbox appearing in the header row which controls the other checkboxes.")]
        protected virtual System.Web.UI.HtmlControls.HtmlInputCheckBox SelectAllControl {
            get {
                return this.selectAllControl;
            }
        }
        #endregion

        #region Properties
        /// <summary>
        /// Gets or sets the behavior of including a checkbox in the Header area which selects all the row checkboxes based on its value.
        /// </summary>
        /// <remarks>This behavior will only exist on browsers supporting javascript and the W3C DOM.</remarks>
        [
        DefaultValue(false),
        Description("Gets or sets the behavior of including a checkbox in the Header area which selects all the row checkboxes based on its value.")
        ]
        public virtual Boolean AllowSelectAll {
            get {
                object savedState = null;
                savedState = this.ViewState["AllowSelectAll"];
                if ( savedState != null ) {
                    return (Boolean)savedState;
                }
                return false;
            }
            set {
                this.ViewState["AllowSelectAll"] = value;
            }
        }

        /// <summary>
        /// Gets or sets the selection mode of the <see cref="RowSelectorColumn"/>.
        /// </summary>
        /// <remarks>
        /// Use the SelectionMode property to specify the mode behavior of the <see cref="RowSelectorColumn"/>.
        /// Setting this property to ListSelectionMode.Single indicates only a single item can be selected, while ListSelectionMode.Multiple specifies multiple items can be selected.
        /// </remarks>
        [
        DefaultValue(ListSelectionMode.Multiple),
        Description("Gets or sets the selection mode of the RowSelectorColumn.")
        ]
        public virtual ListSelectionMode SelectionMode {
            get {
                object savedState = null;
                savedState = this.ViewState["SelectionMode"];
                if ( savedState != null ) {
                    return (ListSelectionMode)savedState;
                }
                return ListSelectionMode.Multiple;
            }
            set {
                this.ViewState["SelectionMode"] = value;
            }
        }

        /// <summary>
        /// Gets an array of the DataGridItem indexes which are marked as selected.
        /// </summary>
        /// <remarks>The index can be used to get, for example, in the DataKeys collection to get the keys for the selected rows.</remarks>
        [
        Browsable(false),
        Description("Gets an array of the DataGridItem indexes which are marked as selected.")
        ]
        public virtual Int32[] SelectedIndexes {
            get {
                System.Collections.ArrayList selectedIndexList = new System.Collections.ArrayList();
                Int32 thisCellIndex = this.Owner.Columns.IndexOf(this);
                foreach( DataGridItem item in this.Owner.Items ) {
                    Control foundControl = item.FindControl("RowSelectorColumnSelector");
                    System.Web.UI.HtmlControls.HtmlInputCheckBox Checkselector = foundControl as System.Web.UI.HtmlControls.HtmlInputCheckBox;
                    System.Web.UI.HtmlControls.HtmlInputRadioButton radioselector = foundControl as System.Web.UI.HtmlControls.HtmlInputRadioButton;
                    if ( Checkselector != null && Checkselector.Checked )  {
                        selectedIndexList.Add( item.ItemIndex );
                    } else if ( radioselector != null && radioselector.Checked )  {
                        selectedIndexList.Add( item.ItemIndex );
                    }
                }
                return (Int32[])selectedIndexList.ToArray(typeof( System.Int32 ) );
            }
        }

        #endregion

        #region SelectAll Script
        /// <summary>
        /// Applies to the SelectAll checkbox the javascript neccessary to create its behavior.
        /// </summary>
        [ Description("Applies to the SelectAll checkbox the javascript neccessary to create its behavior.")]
        protected virtual void ApplyScriptToSelectAllCheckBox() {
            selectAllControl.Attributes["onclick"] = "RowSelectorColumn_SelectAll( this );";
        }

        /// <summary>
        /// Emits the script library neccessary for the SelectAll behavior.
        /// </summary>
        [Description("Emits the script library neccessary for the SelectAll behavior.")]
        protected virtual void RegisterSelectAllScript() {
            if ( this.Owner.Page != null ) {
                if ( !this.Owner.Page.IsClientScriptBlockRegistered("RowSelectorColumn Library") ) {

                    ResourceManager manager = new ResourceManager( this.GetType() );
                    String script = manager.GetResourceSet(System.Globalization.CultureInfo.CurrentCulture, true, true).GetString("W3Cscript");
                    this.Owner.Page.RegisterClientScriptBlock("RowSelectorColumn Library", script );

                }
            }
        }


        /// <summary>
        /// Registers the given checkbox as being bound to the SelectAll checkbox.
        /// </summary>
        /// <param name="selector">The checkbox being bound.</param>
        [Description("Registers the given checkbox as being bound to the SelectAll checkbox.")]
        protected virtual void RegisterForSelectAll( ParticipantCheckBox selector ) {
            selector.Master = this.selectAllControl;
        }

        #endregion

        #region Private
        private void selectorDataBinding( Object sender, EventArgs e ) {
            ParticipantRadioButton radio = sender as ParticipantRadioButton;
            if ( radio != null ) {
                this.SetIndexValue( radio );
            }
        }
        private System.Web.UI.HtmlControls.HtmlInputCheckBox selectAllControl;
        #endregion

        #region Participant Controls
        /// <summary>
        /// The checkboxes which appear in each cell of a <see cref="RowSelectorColumn"/> when <see cref="RowSelectorColumn.SelectionMode"/> is set to <see cref="ListSelectionMode.Multiple"/>.
        /// </summary>
        public class ParticipantCheckBox : System.Web.UI.HtmlControls.HtmlInputCheckBox {
            /// <summary>
            /// Creates a new instance of the <see cref="ParticipantCheckBox"/> class.
            /// </summary>
            public ParticipantCheckBox() : base() {
            }


            /// <summary>
            /// Overrides <see cref="HtmlControl.Render"/>.
            /// </summary>
            protected override void Render( HtmlTextWriter writer ) {
                base.Render(writer);
                if ( master != null ) {
                    LiteralControl script = new LiteralControl("/r/n<script language='javascript'>/r/nRowSelectorColumn_Register('" + master.ClientID + "', '" + this.ClientID + "')/r/n</script>");
                    script.RenderControl(writer);
                }
            }

            /// <summary>
            /// Gets or sets the checkbox which controls the checked state of this checkbox.
            /// </summary>
            public Control Master {
                get {
                    return this.master;
                }
                set {
                    this.master = value;
                }
            }

            private Control master;

            /// <summary>
            /// Overrides <see cref="HtmlInputCheckBox.OnPreRender"/>.
            /// </summary>
            protected override void OnPreRender(System.EventArgs e) {
                if ( master != null ) {
                    this.Attributes["onclick"] = "RowSelectorColumn_CheckChildren( '" + this.Master.ClientID + "' );";
                }
                base.OnPreRender(e);
            }

        }

        /// <summary>
        /// The radiobutton which appears in each cell of a <see cref="RowSelectorColumn"/> when <see cref="RowSelectorColumn.SelectionMode"/> is set to <see cref="ListSelectionMode.Single"/>.
        /// </summary>
        public class ParticipantRadioButton : System.Web.UI.HtmlControls.HtmlInputRadioButton, IPostBackDataHandler {
            /// <summary>
            /// Creates a new instance of the <see cref="ParticipantRadioButton"/> class.
            /// </summary>
            public ParticipantRadioButton() : base() {
            }

            IPostBackDataHandler Implementation

            /// <summary>
            /// Overrides <see cref="HtmlInputRadioButton.RenderAttributes"/>.
            /// </summary>
            /// <remarks>Customized to use this implementation of RenderedNameAttribute</remarks>
            protected override void RenderAttributes(HtmlTextWriter writer ) {
                writer.WriteAttribute("value", this.Value);
                this.Attributes.Remove("value");
                writer.WriteAttribute("name", this.RenderedNameAttribute);
                this.Attributes.Remove("name");
                if (this.ID != null) {
                    writer.WriteAttribute("id", this.ClientID);
                }
                this.Attributes.Render(writer);
                writer.Write(" /");
            }


            /// <summary>
            /// Gets the final rendering of the Name attribute.
            /// </summary>
            /// <remarks>
            /// Differs from the standard RenderedNameAttribute to use the column as the logical naming container instead of the row.
            /// </remarks>
            protected virtual String RenderedNameAttribute {
                get {
                    this.DiscoverContainers();
                    if ( parentCell == null || parentDataGridItem == null || parentDataGrid == null ) {
                        return this.Name;
                    } else {
                        System.Text.StringBuilder groupContainer = new System.Text.StringBuilder();
                        groupContainer.Append( parentDataGrid.UniqueID );
                        groupContainer.Append( ":Column" );
                        groupContainer.Append( parentDataGridItem.Cells.GetCellIndex(parentCell).ToString() );
                        groupContainer.Append( ":" );
                        groupContainer.Append( this.Name );

                        return groupContainer.ToString();
                    }
                }
            }

            private TableCell parentCell;
            private DataGridItem parentDataGridItem;
            private DataGrid parentDataGrid;

            /// <summary>
            /// Looks up the control heirarchy to discover the container controls for this radiobutton
            /// </summary>
            protected virtual void DiscoverContainers() {
                if ( parentCell == null || parentDataGridItem == null || parentDataGrid == null ) {
                    Control tempControl = this.NamingContainer;
                    if ( tempControl is DataGridItem ) {
                        parentDataGridItem = (DataGridItem)tempControl;
                        parentDataGrid = (DataGrid)parentDataGridItem.NamingContainer;
                    }

                    tempControl = this.Parent;
                    while( tempControl.Parent.UniqueID != parentDataGridItem.UniqueID ) {
                        tempControl = tempControl.Parent;
                    }
                    if ( tempControl is TableCell ) {
                        parentCell = (TableCell)tempControl;
                    }
                }
            }

            
        }
        #endregion

    }
}
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