ASP.Net Web Forms Syntax

Following are some useful syntax to write ASP.Net/C# code in Html content:

1) Rendering Code Syntax: <% %> and <%= %>

The following example demonstrates the usage of above syntax:

<% for (int i=0; i<8; i++) { %>
     <font size="<%=i%>"> Hello World! </font> <br>
<% } %>

Code enclosed by <% ... %> is just executed, while expressions that include an equal sign, <%= ... %>, are evaluated and the result is emitted as content. Therefore <%="Hello World" %> renders the same thing as the C# code <% Response.Write("Hello World"); %>.

Note: In case of C# language it is important to place semicolon (;) correctly to end or separate statements.



2) Data Binding Syntax: <%# %>

Code located within a <%# %> code block is only executed when the DataBind method of its parent control container is invoked. The following example demonstrates how to use the data binding syntax within an <asp:datalist runat=server> control.

Within the datalist, the template for one item is specified. The content of the item template is specified using a data binding expression and the Container.DataItem refers to the data source used by the datalist MyList.

<asp:datalist id="MyList" runat=server>
  <ItemTemplate>
    Here is a value: <%# Container.DataItem %>
  </ItemTemplate>
</asp:datalist>

In this case the data source of the MyList control is set programmatically, and then DataBind() is called.

void Page_Load(Object sender, EventArgs e) {
  ArrayList items = new ArrayList();

  items.Add("One");
  items.Add("Two");
  items.Add("Three");

  MyList.DataSource = items;
  MyList.DataBind();
}

Calling the DataBind method of a control causes a recursive tree walk from that control on down in the tree; the DataBinding event is raised on each server control in that hierarchy, and data binding expressions on the control are evaluated accordingly. So, if the DataBind method of the page is called, then every data binding expression within the page will be called.



3) Server-Side Comment Syntax: <%-- Comment --%>

The following sample demonstrates how to block content from executing and being sent down to a client.

<%--
  <asp:calendar id="MyCal" runat=server/>
    <% for (int i=0; i<45; i++) { %>
             Hello World <br>
    <% } %>
--%>

4) Server-Side Include Syntax: <-- #Include File="Locaton.inc" -->

Server-side #Includes enable developers to insert the raw contents of a specified file anywhere within an ASP.NET page. The following sample demonstrates how to insert a custom header and footer within a page.

<!-- #Include File="Header.inc" -->
...
<!-- #Include File="Footer.inc" -->

5) Expression Syntax: <%$ ... %> (New in ASP.Net 2.0 )

ASP.NET 2.0 adds a new declarative expression syntax for substituting values into a page before the page is parsed. This is useful for substituting connection string values or application settings defined in a Web.config file for server control property values. It can also be used to substitute values from a resource file for locaization.

<asp:SqlDataSource ID="SqlDataSource1" 
        ConnectionString='<%$ connectionStrings:Pubs %>' 
        runat="server" SelectCommand="sp_GetAuthors" />

<asp:Label ID="Label1" 
        Text='<%$ Resources: ExchRate, ConvertLabel %>' 
        runat="server"/>

To see the practical usage of above syntax you can refer following post:
Custom paging in ASP.Net GridView control


Reference:
Web Forms Syntax Reference

Custom paging in ASP.Net GridView control

In one of my application I tried to copy the Paging style of SharePoint's ListView WebPart, so in that process I find a way to implement custom paging in ASP.Net GridView.
So this article basically describes how we can implement custom paging style in ASP.Net GridView control.


Following is the snapshot of GridView with custom paging :



HTML code for related custom paging :

<asp:GridView ID="gridView" runat="server" PageSize="5" 

    . . .

   <PagerTemplate>
                                                                                     


   <% if (gridView.PageIndex > 0) { %>

       <asp:ImageButton ID="imgBtnPrevious" runat="server" 
           Style="vertical-align: middle;" 
           ImageUrl="/_layouts/1033/images/prev.gif"
           CommandArgument="Prev" CommandName="Page" />
                                        

   <% } %>
                                                                                     

  
   <%=(gridView.PageIndex * 5) + 1%>
    - <%=(gridView.PageIndex * 5) + gridView.Rows.Count%>

  
   <% if (gridView.PageIndex != (gridView.PageCount - 1)) { %>
                                                             
         <asp:ImageButton ID="imgBtnNext" runat="server" 
           Style="vertical-align: middle;" ImageUrl="/_layouts/1033/images/next.gif" 
           CommandArgument="Next" CommandName="Page" />
                                                                                        <% } %>
                                                                                        </PagerTemplate>

    . . .

</asp:GridView> 

 
 
 
 
There are two if conditions in the above code, first to hide the left arrow image on GridView's first page and second to hide the right arrow image on GridView's last page display (by using PageIndex and PageCount).

Note : In the above code, I used the default images (left-right arrow) provided by SharePoint.



CSharp (C#) code to handle GridView RowCommand event:

void gridView_OnRowCommand(object sender, CommandEventArgs e)
{
    try
    {
        //Get the current page selected
        int intCurIndex = gridView.PageIndex;
        //Switch-Case to handle to Previous and Next paging
        switch (e.CommandArgument.ToString().ToLower())
        {
            case "prev":
                if (intCurIndex > 0)
                    gridView.PageIndex = intCurIndex - 1;
                break;

            case "next":
                if (intCurIndex < gridView.PageCount - 1)
                    gridView.PageIndex = intCurIndex + 1;
                break;
        }

        // popultate the gridview control
        DataSet dataset = getDataSet();
        //Set the DataSource of GridView and call DataBind
        gridView.DataSource = dataset;
        gridView.DataBind();
    }
    catch (Exception)
    {
        throw;
    }
}

I used following table to get the logic for writing page number (just for reference):

Index    (Index*5)+1    (Index*5)+RowCount    Final Display
0        0*5 + 1 = 1     0*5 + 5 = 5          1  - 5
1        1*5 + 1 = 6     1*5 + 5 = 10         6  - 10
2        2*5 + 1 = 11    2*5 + 5 = 15         11 - 15
3        3*5 + 1 = 16    3*5 + 5 = 20         16 - 20
4        4*5 + 1 = 21    4*5 + 5 = 25         21 - 25

 
 
Note : Here the GridView's PageSize is 5.

 
 
Reference:
Custom Paging in GridView Control

Error handling in JavaScript

One way to handle error in JavaScript is to use simple try-catch block.

function foo(flag)
{
    try
    {
        //Your code
    }
    catch(exception)
    {
        //Log exception in error log using exception object
    }
} 

In the above approach we have to write try-catch in all required functions.

Second approach is to register a function on window object which will get called always. It is similar to Page_Error function implementation in ASP.Net.

//Register handleError function to handles all browser error messages 
window.onerror = handleError;

//Function to handle all errors.
function handleError(exception) 
{
    //Perform log operation
    return true;
}

References :
JavaScript Error Handling

Error Handling

Error handling in javascript

Resource file usage in .Net

This article describes how we can consume values from Resource file in various scenarios.

1) Consume resource value in C# code :

btnCancel.Text = Resources.myResource.ButtonCancel;

2) Consume resource value in HTML / Client control in HTML code :

<input type="button" id="btnAdd" text="<%= Resources.myResource.ButtonAdd %>" />

3) Consume resource value in Server control in HTML code :

<asp:ListItem Text="<%$ Resources:myResource, Yes%>"></asp:ListItem>

4) Consume resource value to set some para / span text in HTML code :

<p>
 <asp:Literal runat="server" Text="<%$ Resources:myResource, Success%>" />
</p>

Note : In the above code, myResource is resource file name.

What I get the conclusion by implementing above scenarions are that :
In case of C# code, resource value usage is straight, just Resources.resourceFileName.keyName.
Whereas in case of HTML / ASP.Net code, if I am using HTML / Client control then we have to use "<%= ... %>" (percentage symbol) and in case of Server control we have use "<$= ... %>" (dollar symbol).

To change style (CSS) of menuitem in SharePoint

This article describes how we can change the style (CSS) of menuitem in SharePoint.

Open the following file (preferably in Visual Studio IDE):

C:\Program Files\Common Files\Microsoft Shared\web server extensions\12\TEMPLATE\LAYOUTS\1033\STYLES\Core.css

To change menuitem cell (Line 1345 --- aprox) :

.ms-menuimagecell
{
    background:Maroon
    /*background:#ffe6a0 */ 

    url("/_layouts/images/selectednav.gif") 
    repeat-x;
    cursor:pointer;
    border:solid 1px #ffffff;
    padding:0px;
    height:18px;
}

To change menuitem - OnHover (Line 4012 --- aprox) :

.ms-MenuUIItemTableHover
{
    background-color:Blue;
    border:1px solid Red;

    /*background-color:#ffe6a0;
    border:1px solid #d2b47a;*/
}

Note : Before making any changes, don't forget to keep the back-up copy of Core.css

Following will be the effect of above changes :

Customize --- "Welcome UserName" control in SharePoint

This article describes how we can customize --- "Welcome UserName" control in SharePoint.



To edit the existing Welcome control in sharePoint, first you have to open the following file (preferably in Visual Studio IDE):

C:\Program Files\Common Files\Microsoft Shared\web server extensions\12\TEMPLATE\CONTROLTEMPLATES\Welcome.ascx

<%@ Register Tagprefix="SharePoint" Namespace="Microsoft.SharePoint.WebControls" Assembly="Microsoft.SharePoint, Version=12.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c" %> 
<%@ Register Tagprefix="Utilities" Namespace="Microsoft.SharePoint.Utilities" Assembly="Microsoft.SharePoint, Version=12.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c" %> 
<%@ Import Namespace="Microsoft.SharePoint" %>
<%@ Control Language="C#" Inherits="Microsoft.SharePoint.WebControls.Welcome,Microsoft.SharePoint,Version=12.0.0.0,Culture=neutral,PublicKeyToken=71e9bce111e9429c"   AutoEventWireup="false" compilationMode="Always" %>
  <SharePoint:PersonalActions AccessKey="<%$Resources:wss,personalactions_menu_ak%>" ToolTip="<%$Resources:wss,open_menu%>" runat="server" id="ExplicitLogout" Visible="false">
      <CustomTemplate>
       <SharePoint:FeatureMenuTemplate runat="server"
             FeatureScope="Site"
             Location="Microsoft.SharePoint.StandardMenu"
             GroupId="PersonalActions"
             id="ID_PersonalActionMenu"
             UseShortId="true" Visible="true" 
             >
             <SharePoint:MenuItemTemplate runat="server" id="ID_PersonalInformation"
                         Text="1 <%$Resources:wss,personalactions_personalinformation%>"
                         Description="<%$Resources:wss,personalactions_personalinformationdescription%>"
                         MenuGroupId="100"
                         Sequence="100"
                         ImageUrl="/_layouts/images/menuprofile.gif"
                         UseShortId="true" Visible="false"
                         />
             <SharePoint:MenuItemTemplate runat="server" id="ID_LoginAsDifferentUser"
                         Text="2 <%$Resources:wss,personalactions_loginasdifferentuser%>"
                         Description="<%$Resources:wss,personalactions_loginasdifferentuserdescription%>"
                         MenuGroupId="200"
                         Sequence="100"
                         UseShortId="true"
                         />
             <SharePoint:MenuItemTemplate runat="server" id="ID_RequestAccess"
                         Text="3 <%$Resources:wss,personalactions_requestaccess%>"
                         Description="<%$Resources:wss,personalactions_requestaccessdescription%>"
                         MenuGroupId="200"
                         UseShortId="true"
                         Sequence="200"
                         />
             <SharePoint:MenuItemTemplate runat="server" id="ID_Logout"
                         Text="4 <%$Resources:wss,personalactions_logout%>"
                         Description="<%$Resources:wss,personalactions_logoutdescription%>"
                         MenuGroupId="200"
                         Sequence="300"
                         UseShortId="true" Visible="false"
                         />
             <SharePoint:MenuItemTemplate runat="server" id="ID_PersonalizePage"
                         Text="5 <%$Resources:wss,personalactions_personalizepage%>"
                         Description="<%$Resources:wss,personalactions_personalizepagedescription%>"
                         ImageUrl="/_layouts/images/menupersonalize.gif"
                         ClientOnClickScript="javascript:MSOLayout_ChangeLayoutMode(true);"
                         PermissionsString="AddDelPrivateWebParts,UpdatePersonalWebParts"
                         PermissionMode="Any"
                         MenuGroupId="300"
                         Sequence="100"
                         UseShortId="true"
                         /> 
             <SharePoint:MenuItemTemplate runat="server" id="ID_SwitchView"
                         MenuGroupId="300"
                         Sequence="200"
                         UseShortId="true"
                         />
             <SharePoint:MenuItemTemplate runat="server" id="MSOMenu_RestoreDefaults"
                         Text="6 <%$Resources:wss,personalactions_restorepagedefaults%>"
                         Description="<%$Resources:wss,personalactions_restorepagedefaultsdescription%>"
                         ClientOnClickNavigateUrl="javascript:MSOWebPartPage_RestorePageDefault()"
                         MenuGroupId="300"
                         Sequence="300"
                         UseShortId="true"
                         />
       </SharePoint:FeatureMenuTemplate>
       mmm
      </CustomTemplate>
</SharePoint:PersonalActions>
<SharePoint:ApplicationPageLink runat="server" id="ExplicitLogin"
      ApplicationPageFileName="Authenticate.aspx" AppendCurrentPageUrl=true
      Text="<%$Resources:wss,login_pagetitle%>" style="display:none" Visible="true" />

Note : The above code is modified one... so don't copy-paste it exactly. Also keep the back-up of your original file :)

To hide a particular menuitem, either you can delete its code from the file or set its Visible property to false (as specified in above code for menuitem 1 & 4).

Following will be the result of above code:




To add a new menuitem, you can refer following article:
Custom-action-locations-and-groupid (to add extra menu in drop down)

Dot Net Tips n Tricks

1) To set the textbox's Text property having TextBoxMode property set to Password:
In case of normal textbox, we change its Text property by writing following code :

TextBox txtSample = new TextBox();
txtSample.Text = "Sample";

But in case if we are using textbox for Password purpose, then we have to set its TextBoxMode to Password. So to change its Text property we have to use following code:

TextBox txtPassword = new TextBox();
if (txtPassword.TextMode == TextBoxMode.Password)
{
    //newValue is the new value that we want to set.    
    txtPassword.Attributes.Add("value", newValue);
}

2) Code to remove HTML contents from a string :

public string RemoveHTML(string strHTML)
{
    //System.Web.HttpContext.Current.Server.HtmlDecode
    return Server.HtmlDecode(Regex.Replace(strHTML, "<(.|\n)*?>", ""));
}