Column.cs source code in C# .NET

                        Code:
                         / FXUpdate3074 / FXUpdate3074 / 1.1 / untmp / whidbey / QFE / ndp / fx / src / xsp / System / Web / UI / WebControls / Column.cs / 1 / Column.cs
                        
                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

namespace System.Web.UI.WebControls { 
 
    using System;
    using System.Collections; 
    using System.ComponentModel;
    using System.Web;
    using System.Web.UI;
    using System.Security.Permissions; 

 
    ///  
    ///    Creates a column and is the base class for all  column types.
    ///  
    [
    TypeConverterAttribute(typeof(ExpandableObjectConverter))
    ]
    [AspNetHostingPermission(SecurityAction.LinkDemand, Level=AspNetHostingPermissionLevel.Minimal)] 
    [AspNetHostingPermission(SecurityAction.InheritanceDemand, Level=AspNetHostingPermissionLevel.Minimal)]
    public abstract class DataGridColumn : IStateManager { 
 
        private DataGrid owner;
        private TableItemStyle itemStyle; 
        private TableItemStyle headerStyle;
        private TableItemStyle footerStyle;
        private StateBag statebag;
        private bool marked; 

 
 
        /// 
        /// Initializes a new instance of the System.Web.UI.WebControls.Column class. 
        /// 
        protected DataGridColumn() {
            statebag = new StateBag();
        } 

 
        ///  
        ///    [To be supplied.]
        ///  
        protected bool DesignMode {
            get {
                if (owner != null) {
                    return owner.DesignMode; 
                }
                return false; 
            } 
        }
 

        /// 
        ///    Gets the style properties for the footer item.
        ///  
        [
        WebCategory("Styles"), 
        DefaultValue(null), 
        WebSysDescription(SR.DataGridColumn_FooterStyle),
        DesignerSerializationVisibility(DesignerSerializationVisibility.Content), 
        PersistenceMode(PersistenceMode.InnerProperty)
        ]
        public virtual TableItemStyle FooterStyle {
            get { 
                if (footerStyle == null) {
                    footerStyle = new TableItemStyle(); 
                    if (IsTrackingViewState) 
                        ((IStateManager)footerStyle).TrackViewState();
                } 
                return footerStyle;
            }
        }
 

        ///  
        ///  
        internal TableItemStyle FooterStyleInternal {
            get { 
                return footerStyle;
            }
        }
 

        ///  
        ///     Gets or sets the text displayed in the footer of the 
        ///    System.Web.UI.WebControls.Column.
        ///  
        [
        WebCategory("Appearance"),
        DefaultValue(""),
        WebSysDescription(SR.DataGridColumn_FooterText) 
        ]
        public virtual string FooterText { 
            get { 
                object o = ViewState["FooterText"];
                if (o != null) 
                    return(string)o;
                return String.Empty;
            }
            set { 
                ViewState["FooterText"] = value;
                OnColumnChanged(); 
            } 
        }
 

        /// 
        ///    Gets or sets the URL reference to an image to display
        ///       instead of text on the header of this System.Web.UI.WebControls.Column 
        ///       .
        ///  
        [ 
        WebCategory("Appearance"),
        DefaultValue(""), 
        UrlProperty(),
        WebSysDescription(SR.DataGridColumn_HeaderImageUrl)
        ]
        public virtual string HeaderImageUrl { 
            get {
                object o = ViewState["HeaderImageUrl"]; 
                if (o != null) 
                    return(string)o;
                return String.Empty; 
            }
            set {
                ViewState["HeaderImageUrl"] = value;
                OnColumnChanged(); 
            }
        } 
 

        ///  
        /// Gets the style properties for the header of the System.Web.UI.WebControls.Column. This property is read-only.
        /// 
        [
        WebCategory("Styles"), 
        DefaultValue(null),
        WebSysDescription(SR.DataGridColumn_HeaderStyle), 
        DesignerSerializationVisibility(DesignerSerializationVisibility.Content), 
        PersistenceMode(PersistenceMode.InnerProperty)
        ] 
        public virtual TableItemStyle HeaderStyle {
            get {
                if (headerStyle == null) {
                    headerStyle = new TableItemStyle(); 
                    if (IsTrackingViewState)
                        ((IStateManager)headerStyle).TrackViewState(); 
                } 
                return headerStyle;
            } 
        }


        ///  
        /// 
        internal TableItemStyle HeaderStyleInternal { 
            get { 
                return headerStyle;
            } 
        }


        ///  
        ///    Gets or sets the text displayed in the header of the
        ///    System.Web.UI.WebControls.Column. 
        ///  
        [
        WebCategory("Appearance"), 
        DefaultValue(""),
        WebSysDescription(SR.DataGridColumn_HeaderText)
        ]
        public virtual string HeaderText { 
            get {
                object o = ViewState["HeaderText"]; 
                if (o != null) 
                    return(string)o;
                return String.Empty; 
            }
            set {
                ViewState["HeaderText"] = value;
                OnColumnChanged(); 
            }
        } 
 

        ///  
        /// Gets the style properties of an item within the System.Web.UI.WebControls.Column. This property is read-only.
        /// 
        [
        WebCategory("Styles"), 
        DefaultValue(null),
        WebSysDescription(SR.DataGridColumn_ItemStyle), 
        DesignerSerializationVisibility(DesignerSerializationVisibility.Content), 
        PersistenceMode(PersistenceMode.InnerProperty)
        ] 
        public virtual TableItemStyle ItemStyle {
            get {
                if (itemStyle == null) {
                    itemStyle = new TableItemStyle(); 
                    if (IsTrackingViewState)
                        ((IStateManager)itemStyle).TrackViewState(); 
                } 
                return itemStyle;
            } 
        }


        ///  
        /// 
        internal TableItemStyle ItemStyleInternal { 
            get { 
                return itemStyle;
            } 
        }


        ///  
        /// Gets the System.Web.UI.WebControls.DataGrid that the System.Web.UI.WebControls.Column is a part of. This property is read-only.
        ///  
        protected DataGrid Owner { 
            get {
                return owner; 
            }
        }

 
        /// 
        /// Gets or sets the expression used when this column is used to sort the data source> by. 
        ///  
        [
        WebCategory("Behavior"), 
        DefaultValue(""),
        WebSysDescription(SR.DataGridColumn_SortExpression)
        ]
        public virtual string SortExpression { 
            get {
                object o = ViewState["SortExpression"]; 
                if (o != null) 
                    return(string)o;
                return String.Empty; 
            }
            set {
                ViewState["SortExpression"] = value;
                OnColumnChanged(); 
            }
        } 
 

        ///  
        /// Gets the statebag for the System.Web.UI.WebControls.Column. This property is read-only.
        /// 
        protected StateBag ViewState {
            get { 
                return statebag;
            } 
        } 

 
        /// 
        /// Gets or sets a value to indicate whether the System.Web.UI.WebControls.Column is visible.
        /// 
        [ 
        WebCategory("Behavior"),
        DefaultValue(true), 
        WebSysDescription(SR.DataGridColumn_Visible) 
        ]
        public bool Visible { 
            get {
                object o = ViewState["Visible"];
                if (o != null)
                    return(bool)o; 
                return true;
            } 
            set { 
                ViewState["Visible"] = value;
                OnColumnChanged(); 
            }
        }

 
        /// 
        ///  
        public virtual void Initialize() { 
        }
 

        /// 
        /// Initializes a cell in the System.Web.UI.WebControls.Column.
        ///  
        public virtual void InitializeCell(TableCell cell, int columnIndex, ListItemType itemType) {
            switch (itemType) { 
                case ListItemType.Header: 
                    {
                        WebControl headerControl = null; 
                        bool sortableHeader = true;
                        string sortExpression = null;

                        if ((owner != null) && (owner.AllowSorting == false)) { 
                            sortableHeader = false;
                        } 
                        if (sortableHeader) { 
                            sortExpression = SortExpression;
                            if (sortExpression.Length == 0) 
                                sortableHeader = false;
                        }

                        string headerImageUrl = HeaderImageUrl; 
                        if (headerImageUrl.Length != 0) {
                            if (sortableHeader) { 
                                ImageButton sortButton = new ImageButton(); 

                                sortButton.ImageUrl = HeaderImageUrl; 
                                sortButton.CommandName = DataGrid.SortCommandName;
                                sortButton.CommandArgument = sortExpression;
                                sortButton.CausesValidation = false;
                                headerControl = sortButton; 
                            }
                            else { 
                                Image headerImage = new Image(); 

                                headerImage.ImageUrl = headerImageUrl; 
                                headerControl = headerImage;
                            }
                        }
                        else { 
                            string headerText = HeaderText;
                            if (sortableHeader) { 
                                LinkButton sortButton = new DataGridLinkButton(); 

                                sortButton.Text = headerText; 
                                sortButton.CommandName = DataGrid.SortCommandName;
                                sortButton.CommandArgument = sortExpression;
                                sortButton.CausesValidation = false;
                                headerControl = sortButton; 
                            }
                            else { 
                                if (headerText.Length == 0) { 
                                    // the browser does not render table borders for cells with nothing
                                    // in their content, so we add a non-breaking space. 
                                    headerText = " ";
                                }
                                cell.Text = headerText;
                            } 
                        }
 
                        if (headerControl != null) { 
                            cell.Controls.Add(headerControl);
                        } 
                    }
                    break;

                case ListItemType.Footer: 
                    {
                        string footerText = FooterText; 
                        if (footerText.Length == 0) { 
                            // the browser does not render table borders for cells with nothing
                            // in their content, so we add a non-breaking space. 
                            footerText = " ";
                        }

                        cell.Text = footerText; 
                    }
                    break; 
            } 
        }
 

        /// 
        /// Determines if the System.Web.UI.WebControls.Column is marked to save its state.
        ///  
        protected bool IsTrackingViewState {
            get { 
                return marked; 
            }
        } 


        /// 
        /// Loads the state of the System.Web.UI.WebControls.Column. 
        /// 
        protected virtual void LoadViewState(object savedState) { 
            if (savedState != null) { 
                object[] myState = (object[])savedState;
 
                if (myState[0] != null)
                    ((IStateManager)ViewState).LoadViewState(myState[0]);
                if (myState[1] != null)
                    ((IStateManager)ItemStyle).LoadViewState(myState[1]); 
                if (myState[2] != null)
                    ((IStateManager)HeaderStyle).LoadViewState(myState[2]); 
                if (myState[3] != null) 
                    ((IStateManager)FooterStyle).LoadViewState(myState[3]);
            } 
        }


        ///  
        ///    Marks the starting point to begin tracking and saving changes to the
        ///       control as part of the control viewstate. 
        ///  
        protected virtual void TrackViewState() {
            marked = true; 
            ((IStateManager)ViewState).TrackViewState();
            if (itemStyle != null)
                ((IStateManager)itemStyle).TrackViewState();
            if (headerStyle != null) 
                ((IStateManager)headerStyle).TrackViewState();
            if (footerStyle != null) 
                ((IStateManager)footerStyle).TrackViewState(); 
        }
 

        /// 
        /// Raises the ColumnChanged event for a System.Web.UI.WebControls.Column.
        ///  
        protected virtual void OnColumnChanged() {
            if (owner != null) { 
                owner.OnColumnsChanged(); 
            }
        } 


        /// 
        /// Saves the current state of the System.Web.UI.WebControls.Column. 
        /// 
        protected virtual object SaveViewState() { 
            object propState = ((IStateManager)ViewState).SaveViewState(); 
            object itemStyleState = (itemStyle != null) ? ((IStateManager)itemStyle).SaveViewState() : null;
            object headerStyleState = (headerStyle != null) ? ((IStateManager)headerStyle).SaveViewState() : null; 
            object footerStyleState = (footerStyle != null) ? ((IStateManager)footerStyle).SaveViewState() : null;

            if ((propState != null) ||
                (itemStyleState != null) || 
                (headerStyleState != null) ||
                (footerStyleState != null)) { 
                return new object[4] { 
                    propState,
                    itemStyleState, 
                    headerStyleState,
                    footerStyleState
                };
            } 

            return null; 
        } 

 
        /// 
        /// 
        internal void SetOwner(DataGrid owner) {
            this.owner = owner; 
        }
 
 
        /// 
        /// Converts the System.Web.UI.WebControls.Column to string. 
        /// 
        public override string ToString() {
            return String.Empty;
        } 

 
 
        /// 
        ///  
        /// Return true if tracking state changes.
        /// 
        bool IStateManager.IsTrackingViewState {
            get { 
                return IsTrackingViewState;
            } 
        } 

 
        /// 
        /// 
        /// Load previously saved state.
        ///  
        void IStateManager.LoadViewState(object state) {
            LoadViewState(state); 
        } 

 
        /// 
        /// 
        /// Start tracking state changes.
        ///  
        void IStateManager.TrackViewState() {
            TrackViewState(); 
        } 

 
        /// 
        /// 
        /// Return object containing state changes.
        ///  
        object IStateManager.SaveViewState() {
            return SaveViewState(); 
        } 
    }
} 


// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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Column.cs source code in C# .NET

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