1 using System;
 2 using System.Collections.Generic;
 3 using System.ComponentModel;
 4 using System.Text;
 5 using System.Web;
 6 using System.Web.UI;
 7 using System.Web.UI.WebControls;
 8 
 9 namespace Annsa.Controls
10 {
11     [DefaultProperty("Text")]
12     [ToolboxData("<{0}:AnnsaTextBox runat=server></{0}:AnnsaTextBox>")]
13     public class AnnsaTextBox : System.Web.UI.WebControls.TextBox
14     {
15         private const string _maxLengthAttributeName = "exMaxLen";
16 
17         public AnnsaTextBox() : base()
18         {
19         }
20 
21         override protected void OnPreRender(EventArgs e) 
22         { 
23             // Ensure default work takes place
24             base.OnPreRender(e);
25 
26             // Configure TextArea support
27             // The System.Web.UI.WebControls.TextBox does not
28             // honour the "MaxLength" attribute when the
29             // "Multiline" textmode is selected.
30             if ( ( this.TextMode == TextBoxMode.MultiLine ) && ( this.MaxLength > 0 ) )
31             {
32                 // If we haven't already, include the supporting
33                 // script that limits the content of textareas.
34                 this.Page.ClientScript.RegisterClientScriptResource(typeof(AnnsaTextBox), 
35                                                                     "Annsa.Controls.TextBoxSupport.js");
36 
37                 // Add an expando attribute to the rendered control which sets 
38                 // its maximum length (using the MaxLength Attribute)
39                 // Using RegisterExpandoAttribute maintains XHTML compliance on
40                 // the rendered page.
41                 //
42                 // Where there is a ScriptManager on the parent page, use it
43                 // to register the attribute - to ensure the control
44                 // works in partial updates (like an AJAX UpdatePanel)
45                 if ( ScriptManager.GetCurrent(this.Page) != null)
46                 {
47                     ScriptManager.RegisterExpandoAttribute( this,
48                                                             this.ClientID,
49                                                             _maxLengthAttributeName,
50                                                             this.MaxLength.ToString(), 
51                                                             true);
52                 }
53                 else
54                 {
55                     this.Page.ClientScript.RegisterExpandoAttribute(this.ClientID, 
56                                                                     _maxLengthAttributeName, 
57                                                                     this.MaxLength.ToString());
58                 }
59 
60                 // Now bind the onkeydown, oninput and onpaste events to
61                 // script that we'll inject in the parent page.
62                 this.Attributes.Add("onkeydown","javascript:return LimitInput(this, event);" );
63                 this.Attributes.Add("oninput",  "javascript:return LimitInput(this, event);" );
64                 this.Attributes.Add("onpaste",  "javascript:return LimitPaste(this, event);" );
65             }
66         }
67     }
68 }
69