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How to Create an HTML Editor for ASP.NET AJAX

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15 Jun 2012LGPL313 min read 1M   20.9K   351  
This article discusses how to create an HTML editor server control specifically for the Microsoft AJAX environment.
/*
HTML Editor for ASP.NET AJAX
Basic Edition

Copyright (c) Winthusiasm, Eric Williams
EMail: mail@winthusiasm.com, eric@winthusiasm.com

This software is free: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as 
published by the Free Software Foundation, either version 3 of
the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.

A copy of the GNU Lesser General Public License should accompany
this software. If not, see <http://www.gnu.org/licenses/>.
*/

Type.registerNamespace("Winthusiasm.HtmlEditor");

Winthusiasm.HtmlEditor.DialogBehavior = function(element)
{
    Winthusiasm.HtmlEditor.DialogBehavior.initializeBase(this, [element]);
    
    this._editorControl = null;
    this._dialogDocument = null;
    this._contentWindow = null;
    
    this.options = null;
    this.colors = null;
    this.name = "";
    this.context = null;
    
    this.editor = null;
    this.document = null;
    this.views = null;
    this.tabs = null;
    this.isIE = false;
    this.isFirefox = false;
    this.isOpera = false;
    this.browserVersion = 0;
    
    this.modalState = null;
}

Winthusiasm.HtmlEditor.DialogBehavior.prototype = 
{
    get_editorControl: function()
    {
        return this._editorControl;
    },
    
    set_editorControl: function(value)
    {
        this._editorControl = value;
    },
    
    get_dialogDocument: function()
    {
        return this._dialogDocument;
    },
    
    set_dialogDocument: function(value)
    {
        this._dialogDocument = value;
    },
    
    get_contentWindow: function()
    {
        return this._contentWindow;
    },
    
    set_contentWindow: function(value)
    {
        this._contentWindow = value;
    },
    
    ExecuteCommand: function(commandName, commandValue)
    {
        this.editor.ExecuteCommand(commandName, commandValue);
    },
    
    GetDesignModeDocument: function()
    {
        return this.editor.designModeDocument;
    },
    
    IsTagName: function(element, tagName)
    {
        return element.tagName.toLowerCase() == tagName;
    },

    IsParent: function(tagName)
    {
        if (this.context && this.IsTagName(this.context.parentElement, tagName))
            return true;
            
        return false;
    },
    
    IsParentOnList: function(tagNames)
    {
        tagNames = tagNames.split(',');
        
        for (var i = 0; i < tagNames.length; i++)
        {
            if (this.IsParent(tagNames[i])) return true;
        }
        
        return false;
    },

    IsTextBox: function(element)
    {
        return (element && this.IsTagName(element, "input") && element.type == "text");
    },
    
    GetValue: function(propertyElement)
    {
        var value = propertyElement.value.trim();
        return value.length == 0 ? null : value;
    },

    GetBorderWidth: function(borderWidthStyle)
    {
        var widthStyle = borderWidthStyle.trim();
        if (widthStyle.length == 0) return "";
        
        var widths = widthStyle.split(' ');
        var lastWidth = "";
        
        for (var i = 0; i < widths.length; i++)
        {
            var width = this.RemoveUnit(widths[0])
            if (width.length == 0) return "";
            if (lastWidth.length > 0 && width != lastWidth) return "";
            
            lastWidth = width;
        }
        
        return lastWidth;
    },
    
    SetElementColors: function(elements, borderColor, backgroundColor, color)
    {
        if (!elements) return;
        
        for (var i = 0; i < elements.length; i++)
        {
            var element = elements[i];
            if (borderColor) element.style.borderColor = borderColor;
            if (backgroundColor) element.style.backgroundColor = backgroundColor;
            if (color) element.style.color = color;
        }
    },
    
    FindOption: function(select, value)
    {
        var findValue = value.trim().toLowerCase();
        var options = select.getElementsByTagName("option");
        
        for (var i = 0; i < options.length; i++)
        {
            if (options[i].value == findValue) return findValue;
        }
        
        return "";
    },
    
    FindTabIndex: function(tab)
    {
        for (var i = 0; i < this.tabs.length; i++)
        {
            if (this.tabs[i] == tab) return i;
        }
        
        return -1;
    },
    
    SelectLabel: function(element)
    {
        var selectedColor = this.colors.selectedTab;
        var unselectedColor = this.colors.table;
        var selectedTextColor = this.colors.selectedTabText;
        var unselectedTextColor = this.colors.text;
        
        var p = element.parentNode;
        while (p.tagName.toLowerCase() != "tr") p = p.parentNode;
        
        var t = p.parentNode;
        for (var i = 0; i < t.childNodes.length; i++)
        {
            var childNode = t.childNodes[i];
            if (childNode.nodeType != 1) continue;
            if (childNode.tagName.toLowerCase() != "tr") continue;
            
            var cells = childNode.getElementsByTagName("td");
            if (cells.length != 2) continue;
            
            var selected = p == childNode;
            cells[0].style.backgroundColor = selected ? selectedColor : unselectedColor;
            cells[0].style.fontWeight = selected ? "bold" : "normal";
            cells[0].style.color = selected ? selectedTextColor : unselectedTextColor;
            
            function FindFocusChild(parentNode)
            {
                var childNodes = parentNode.childNodes;
                
                for (var ii = 0; ii < childNodes.length; ii++)
                {
                    var node = childNodes[ii];
                    if (node.nodeType != 1) continue;
                    
                    var tagName = node.tagName.toLowerCase();
                    if (tagName != "input" && tagName != "select") continue;
                    
                    if (node.focus) return node;
                }
                
                return null;
            }

            if (selected && this.IsTagName(element, "td"))
            {
                var focusChild = FindFocusChild(cells[1]);
                
                if (focusChild)
                    focusChild.focus();
            }
        }
    },
    
    SetTabs: function(selectedTabID)
    {
        var selectedTabColor = this.colors.selectedTab;
        var unselectedTabColor = this.colors.unselectedTab;

        var selectedTabTextColor = this.colors.selectedTabText;
        var unselectedTabTextColor = this.colors.tabText;

        for (var i = 0; i < this.tabs.length; i++)
        {
            var tab = this.tabs[i];
            var selected = tab.id == selectedTabID;

            tab.style.backgroundColor = selected ? selectedTabColor : unselectedTabColor;
            tab.style.color = selected ? selectedTabTextColor : unselectedTabTextColor;
            tab.style.fontWeight = selected ? "bold" : "normal";
        }
    },
    
    RoundTabCorners: function()
    {
        for (var i = 0; i < this.tabs.length; i++)
        {
            var tab = this.tabs[i];
            var leftBottom = tab.ownerDocument.createElement("img");
            var rightBottom = tab.ownerDocument.createElement("img");
            
            var corners = [ leftBottom, rightBottom ];
            
            for (var ii = 0; ii < corners.length; ii++)
            {
                var corner = corners[ii];
                corner.src = this.options.pixelImageUrl;
                corner.height = 1;
                corner.width = 1;
                corner.alt = "";
                corner.style.position = "absolute";
                corner.style.bottom = this.isIE && this.browserVersion < 7 ? "-1px" : "0px";
                corner.style.margin = "0px";
                corner.style.padding = "0px";
                corner.style.backgroundColor = this.colors.body;
                corner.style.fontSize = "0px";
            }
            
            leftBottom.style.left = "0px";
            rightBottom.style.right = "0px";
            
            tab.appendChild(leftBottom);
            tab.appendChild(rightBottom);
        }
    },
    
    FindParent: function(tagName)
    {
        if (this.context == null) return null;
        if (this.IsParent(tagName)) return this.context.parentElement;
        
        if (!this.editor.isIE)
        {
            var sc = this.context.range.startContainer;
            
            if (sc.nodeType == 3 && sc.parentNode.nodeType == 1 && this.IsTagName(sc.parentNode, tagName))
            {
                var r = this.editor.designModeDocument.createRange();
                r.selectNode(sc.parentNode);
                this.context.selection.removeAllRanges();
                this.context.selection.addRange(r);
                this.context.range = r;
                this.context.parentElement = sc.parentNode;
                
                return sc.parentNode; 
            }    
        }
        
        return null;
    },
    
    RemoveUnit: function(valueUnit)
    {
        valueUnit = valueUnit.trim().toLowerCase();
        if (valueUnit.length == 0) return "";
        
        var number = parseInt(valueUnit);
        if (typeof number != "number") return "";

        valueUnit = number.toString();
        
        return valueUnit == "NaN" ? "" : valueUnit;
    },

    OnTextBoxFocus: function(tb)
    {
        this.SelectLabel(tb);
        this.SetElementColors([ tb ], this.colors.selectedTab, this.colors.heading, this.colors.headingText);
    },

    OnTextBoxBlur: function(tb)
    {
        switch (tb.className)
        {
            case "size" :
            case "unit" :
                tb.value = this.RemoveUnit(tb.value);
                break;
            default :
                break;
        }
        
        this.SetElementColors([ tb ], this.colors.body, this.colors.body, this.colors.text);
    },

    OnSelectBoxChange: function(sb, otherValue, otherTextBoxID)
    {
        var showTextBox = sb.value == otherValue ? true : false;
        var otherTextBox = this.document.getElementById(otherTextBoxID);
        otherTextBox.style.display = showTextBox ? "inline" : "none";
        
        if (showTextBox) otherTextBox.focus();
    },
    
    OnTab: function(tab)
    {
        var tabIndex = this.FindTabIndex(tab);
        
        if (this.window.OnBeforeViewChange)
            this.window.OnBeforeViewChange(this.views[tabIndex].id);
        
        for (var i = 0; i < this.tabs.length; i++)
        {
            var selected = i == tabIndex;
            this.views[i].style.display = selected ? "block" : "none";
        }

        if (this.window.OnAfterViewChange)
            this.window.OnAfterViewChange(this.views[tabIndex].id);
        
        this.SetTabs(tab.id);
    },

    UpdateContext: function()
    {
        this.context = this.editor.GetContext();
    },

    Focus: function(elementID)
    {
        this.document.getElementById(elementID).focus();
    },
    
    GetViews: function(viewIDs)
    {
        var IDs = viewIDs.split(',');
        var viewList = new Array(IDs.length);
        
        for (var i = 0; i < IDs.length; i++)
        {
            viewList[i] = this.document.getElementById(IDs[i]);
        }
        
        return viewList;
    },
    
    GetTabs: function(tabIDs)
    {
        var IDs = tabIDs.split(',');
        var tabList = new Array(IDs.length);
        
        for (var i = 0; i < IDs.length; i++)
        {
            tabList[i] = this.document.getElementById(IDs[i]);
        }
        
        return tabList;
    },
    
    InitializeDocument: function()
    {
        this.document.body.style.backgroundColor = this.colors.body;
        this.document.body.style.color = this.colors.text;
    },
    
    InitializeViews: function(viewsID, viewIDs)
    {
        this.document.getElementById(viewsID).style.borderColor = this.colors.selectedTab;
        this.views = this.GetViews(viewIDs);
    },
    
    InitializeTabs: function(tabbarID, tabIDs)
    {
        this.document.getElementById(tabbarID).style.color = this.colors.tabText;

        this.tabs = this.GetTabs(tabIDs);
        this.RoundTabCorners();
        this.SetTabs(this.tabs[0].id);
    },
    
    GetTableInputElements: function(table)
    {
        var inputs = new Array();
        var elements = table.getElementsByTagName("input");
        
        for (var i = 0; i < elements.length; i++)
        {
            if (elements[i].type.toLowerCase() == "button") continue;
            Array.add(inputs, elements[i]);
        }
        
        return inputs;
    },
    
    InitializeTables: function(tableIDs)
    {
        var IDs = tableIDs.split(',');
        
        for (var i = 0; i < IDs.length; i++)
        {
            var table = this.document.getElementById(IDs[i]);
            table.style.backgroundColor = this.colors.table;
            table.style.color = this.colors.text;
            
            this.SetElementColors(table.getElementsByTagName("td"), this.colors.heading);
            this.SetElementColors(this.GetTableInputElements(table), this.colors.body, this.colors.body, this.colors.text);
            this.SetElementColors(table.getElementsByTagName("select"), this.colors.selectedTab, this.colors.heading, this.colors.headingText);
        }
    },
    
    initialize: function()
    {
        Winthusiasm.HtmlEditor.DialogBehavior.callBaseMethod(this, 'initialize');

        this.editor = this.get_editorControl();
        this.document = this.get_dialogDocument();
        this.window = this.get_contentWindow();

        this.options = this.editor.dialogInfo.options;
        this.colors = this.options.colors;
        this.name = this.editor.dialogInfo.current.name;
        this.context = this.editor.dialogInfo.current.context;
        
        this.isIE = this.editor.isIE;
        this.isFirefox = this.editor.isFirefox;
        this.isOpera = this.editor.isOpera;
        this.browserVersion = this.editor.browserVersion;
    },
    
    dispose: function()
    {
        Winthusiasm.HtmlEditor.DialogBehavior.callBaseMethod(this, 'dispose');
    },
    
    EnableElements: function(elements, enabled)
    {
        for (var i = 0; i < elements.length; i++)
        {
            elements[i].disabled = enabled ? false : true;
        }
    },
    
    SetShield: function(shield)
    {
        if (shield)
        {
            this.modalState = new Object();
            this.modalState.tabElements = this.editor.DisableTabElements(this.document.body);

            var dialogBox = $get(this.editor.dialogInfo.elementIDs.dialogBox); 
            this.EnableElements(dialogBox.getElementsByTagName("input"), false);

            this.modalState.modalShield = this.editor.CreateShield(dialogBox, dialogBox.offsetHeight, dialogBox.offsetWidth);
        }
        else if (this.modalState)
        {
            this.editor.RemoveShield(this.modalState.modalShield);
            this.editor.RestoreTabElements(this.modalState.tabElements);

            var dialogBox = $get(this.editor.dialogInfo.elementIDs.dialogBox); 
            this.EnableElements(dialogBox.getElementsByTagName("input"), true);
            
            this.modalState = null;
        }
    }
}

Winthusiasm.HtmlEditor.DialogBehavior.descriptor = 
{
    properties: [ {name: 'editorControl', type: Object },
                  {name: 'dialogDocument', type: Object },
                  {name: 'contentWindow', type: Object } ]
}

Winthusiasm.HtmlEditor.DialogBehavior.registerClass("Winthusiasm.HtmlEditor.DialogBehavior", Sys.UI.Behavior);

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License

This article, along with any associated source code and files, is licensed under The GNU Lesser General Public License (LGPLv3)


Written By
Web Developer Winthusiasm
United States United States
Eric Williams is a .NET and Web developer who has been working with ASP.NET AJAX since the March 2006 Atlas CTP. Eric is the founder of Winthusiasm (winthusiasm.com), a .NET technology company that offers consulting and development services, and Colorado Geographic (coloradogeographic.com).

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