Dane's blog

Good news for .net developer. That is from what i have found on the web.

On November 21, the vice president of Microsoft's .NET Developer division, Scott Guthrie, announced that his group had produced "great jQuery IntelliSense support" in for both Visual Studio 2008 and the free Visual Web Developer 2008 Express package in collaboration with the jQuery development team. This delivers on his promise, made in September, that such support would be forthcoming. Guthrie's blog post has instructions on how to grab and install the proper hotfix to add this capability.

Several programmers have written about this problem in detail. Brad Vincent noted the IntelliSense jQuery bug in a blog entry more than half a year before all the recent hoopla, and James Hart came up with a clever solution to javascript:void(0)the jQuery IntelliSense problem in Visual Studio. Hart's fix is to create a dummy JavaScript file that contains stubs to all of jQuery's calls and link to it within Visual Studio; the editor picks up the dummy APIs and auto-completes based on them, but the end-user's Web browser actually uses the jQuery library. Scott Hanselman has also put together a nice tutorial on working with jQuery inside VS 2008.

or read this for simple solution without installing hotfix http://blogs.msdn.com/webdevtools/archive/2008/10/28/rich-intellisense-for-jquery.aspx

GridView Tips and Tricks using ASP.NET – Part III

The GridView control is quiet a handy control and is the most commonly used control when building an ASP.NET site. The more you work with it, the more you realize how powerful it can be while presenting data.

Moving ahead with our GridView Tips and tricks series, I have added some more tips in this article. The previous two articles on the Tips and Tricks are mentioned below:

GridView Tips and Tricks using ASP.NET 2.0 – Part I

Some More GridView Tips and Tricks using ASP.NET - Part II

For this article, we would be using the following template to populate the GridView.

<title>GridView Tips and Tricks Part 2</title>

</head>

<body>

<div>

<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" DataKeyNames="CategoryID"

DataSourceID="SqlDataSource1" ShowFooter="true" AllowPaging="True" AllowSorting="True"

PageSize="5" OnRowDataBound="GridView1_RowDataBound">

<asp:TemplateField HeaderText="CategoryID" InsertVisible="False" SortExpression="CategoryID">

<asp:Label ID="lblCategoryID" runat="server" Text='<%# Bind("CategoryID") %>'></asp:Label>

</ItemTemplate>

</asp:TemplateField>

<asp:TemplateField HeaderText="CategoryName" SortExpression="CategoryName">

<asp:TextBox ID="txtCategoryName" runat="server" Text='<%# Bind("CategoryName") %>'></asp:TextBox>

</EditItemTemplate>

<asp:Label ID="lblCategoryName" runat="server" Text='<%# Bind("CategoryName") %>'></asp:Label>

</ItemTemplate>

</asp:TemplateField>

<asp:TemplateField HeaderText="Description" SortExpression="Description">

<asp:TextBox ID="txtDesc" runat="server" Text='<%# Bind("Description") %>'></asp:TextBox>

</EditItemTemplate>

<asp:Label ID="lblDesc" runat="server" Text='<%# Bind("Description") %>'></asp:Label>

</ItemTemplate>

</asp:TemplateField>

</Columns>

</asp:GridView>

<asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="Data Source=SUPROTIM;Initial Catalog=Northwind;Integrated Security=True"

ProviderName="System.Data.SqlClient" SelectCommand="SELECT [CategoryID], [CategoryName], [Description] FROM [Categories]"

UpdateCommand="UPDATE [Categories] SET [CategoryName] = @CategoryName, [Description] = @Description WHERE [CategoryID] = @CategoryID"/>

</div>

</form>

</body>

</html>

The web.config holding the connection will look similar to the following:

</connectionStrings>

...

</configuration>

Tip 1: Change the color of a GridView Row based on some condition

protected void GridView1_RowCreated(object sender, GridViewRowEventArgs e)

{

if (e.Row.DataItem != null)

{

DataRowView drv = (DataRowView)e.Row.DataItem;

string catName = Convert.ToString(drv["CategoryName"]);

if (catName.Trim() == "Confections")

e.Row.BackColor = System.Drawing.Color.LightBlue;

}

VB.NET

Protected Sub GridView1_RowCreated(ByVal sender As Object, ByVal e As GridViewRowEventArgs)

If Not e.Row.DataItem Is Nothing Then

Dim drv As DataRowView = CType(e.Row.DataItem, DataRowView)

Dim catName As String = Convert.ToString(drv("CategoryName"))

If catName.Trim() = "Confections" Then

e.Row.BackColor = System.Drawing.Color.LightBlue

End If

End Sub

Tip 2: How to create an Image Command Field Column and add to the GridView at runtime

if (!Page.IsPostBack)

{

CommandField cmdField = new CommandField();

cmdField.ButtonType = ButtonType.Image;

cmdField.SelectImageUrl = "~/Images/Home_Np1.GIF";

cmdField.ShowSelectButton = true;

cmdField.HeaderText = "Select";

GridView1.Columns.Add(cmdField);

GridView1.DataBind();

}

VB.NET

If (Not Page.IsPostBack) Then

Dim cmdField As CommandField = New CommandField()

cmdField.ButtonType = ButtonType.Image

cmdField.SelectImageUrl = "~/Images/Home_Np1.GIF"

cmdField.ShowSelectButton = True

cmdField.HeaderText = "Select"

GridView1.Columns.Add(cmdField)

GridView1.DataBind()

End If

Tip 3: How to display images in the GridView from Filesystem based on an existing Column

Let us imagine that you have a folder ‘Images’ where you have stored images for each category. Eg: 1.GIF, 2.GIF, 3.GIF and so on. Now you want to display a different image based on each CategoryID. So for CategoryID = 1, the image is 1.GIF; for CategoryID=2, the image is 2.GIF and so on.

<asp:TemplateField>

<asp:Image runat="server" ImageUrl='<%# "~/Images/"+ Eval("CategoryID") + ".GIF" %>' >

</asp:Image>

</ItemTemplate>

</asp:TemplateField>

Tip 4: How to Retrieve Images from the database and display it in a GridView

I will assume that we have a image column called CatImg in the Categories table.

The first step would be to create an ImageHandler. In such scenarios such as the gridview, usually prefer to go in for a handler when I have to return binary data directly from the database. It gives more control on the resource returned. Moreover it is a preferred solution when you have to set the image programmatically.

To add a handler, right click project > Add New Item > Generic Handler > ShowImage.ashx. The code shown below, uses the Request.QueryString[“id”] to retrieve the CategoryID from it. The ID is then passed to the ‘ShowCatImage()’ method where the image is fetched from the database and returned in a MemoryStream object. We then read the stream into a byte array. Using the OutputStream.Write(), we write the sequence of bytes to the current stream and you get to see your image.

<%@ WebHandler Language="C#" Class="ShowImage" %>

using System;

using System.Configuration;

using System.Web;

using System.IO;

using System.Data;

using System.Data.SqlClient;

public class ShowImage : IHttpHandler

{

public void ProcessRequest(HttpContext context)

{

Int32 catid;

if (context.Request.QueryString["id"] != null)

catid = Convert.ToInt32(context.Request.QueryString["id"]);

else

throw new ArgumentException("No parameter specified");

context.Response.ContentType = "image/jpeg";

Stream strm = ShowCatImage(catid);

byte[] buffer = new byte[4096];

int byteSeq = strm.Read(buffer, 0, 4096);

while (byteSeq > 0)

{

context.Response.OutputStream.Write(buffer, 0, byteSeq);

byteSeq = strm.Read(buffer, 0, 4096);

}

//context.Response.BinaryWrite(buffer);

}

public Stream ShowCatImage(int catid)

{

string conn = ConfigurationManager.ConnectionStrings["NorthwindConnectionString"].ConnectionString;

SqlConnection connection = new SqlConnection(conn);

string sql = "SELECT catImg FROM Categories WHERE CategoryID = @ID";

SqlCommand cmd = new SqlCommand(sql, connection);

cmd.CommandType = CommandType.Text;

cmd.Parameters.AddWithValue("@ID", catid);

connection.Open();

object img = cmd.ExecuteScalar();

try

{

return new MemoryStream((byte[])img);

}

catch

{

return null;

}

finally

{

connection.Close();

}

public bool IsReusable

{

get

{

return false;

}

VB.NET

<%@ WebHandler Language="vb" Class="ShowImage" %>

Imports System

Imports System.Configuration

Imports System.Web

Imports System.IO

Imports System.Data

Imports System.Data.SqlClient

Public Class ShowImage

Implements IHttpHandler

Public Sub ProcessRequest(ByVal context As HttpContext) Implements IHttpHandler.ProcessRequest

Dim catid As Int32

If Not context.Request.QueryString("id") Is Nothing Then

catid = Convert.ToInt32(context.Request.QueryString("id"))

Else

Throw New ArgumentException("No parameter specified")

End If

context.Response.ContentType = "image/jpeg"

Dim strm As Stream = ShowCatImage(catid)

Dim buffer As Byte() = New Byte(4095){}

Dim byteSeq As Integer = strm.Read(buffer, 0, 4096)

Do While byteSeq > 0

context.Response.OutputStream.Write(buffer, 0, byteSeq)

byteSeq = strm.Read(buffer, 0, 4096)

Loop

'context.Response.BinaryWrite(buffer);

End Sub

Public Function ShowCatImage(ByVal catid As Integer) As Stream

Dim conn As String = ConfigurationManager.ConnectionStrings("NorthwindConnectionString").ConnectionString

Dim connection As SqlConnection = New SqlConnection(conn)

Dim sql As String = "SELECT catImg FROM Categories WHERE CategoryID = @ID"

Dim cmd As SqlCommand = New SqlCommand(sql, connection)

cmd.CommandType = CommandType.Text

cmd.Parameters.AddWithValue("@ID", catid)

connection.Open()

Dim img As Object = cmd.ExecuteScalar()

Try

Return New MemoryStream(CType(img, Byte()))

Catch

Return Nothing

Finally

connection.Close()

End Try

End Function

Public ReadOnly Property IsReusable() As Boolean Implements IHttpHandler.IsReusable

Get

Return False

End Get

End Property

End Class

To access this image in the GridView based on the CategoryID, just add the following:

<asp:TemplateField>

<asp:Image runat="server" ImageUrl='<%# "ShowImage.ashx?id=" + Eval("CategoryID") %>' >

</asp:Image>

</ItemTemplate>

</asp:TemplateField>

Tip 5: How to programmatically enable/disable a control in the GridView when in the Edit Mode

If you want to quickly take a decision whether to enable or disable a control when the user edits the row, then use the Enabled attribute and set it to a method that returns a bool value:

<asp:TemplateField HeaderText="CategoryName" SortExpression="CategoryName">

<asp:TextBox ID="txtCategoryName" runat="server" Enabled='<%# EnableDisableTextBox() %>' Text='<%# Bind("CategoryName") %>'></asp:TextBox>

</EditItemTemplate>

<asp:Label ID="lblCategoryName" runat="server" Text='<%# Bind("CategoryName") %>'></asp:Label>

</ItemTemplate>

</asp:TemplateField>

protected bool EnableDisableTextBox()

{

if (1 == 1)

return false;

}

VB.NET

Protected Function EnableDisableTextBox() As Boolean

If 1 = 1 Then

Return False

End If

End Function

You can test this code by adding a CommandField to the GridView as shown below

<asp:CommandField ButtonType="Link" ShowEditButton="true" />

Tip 6: How to insert an Image in between Rows of a GridView using ASP.NET

Please check my article on the same over here

http://www.dotnetcurry.com/ShowArticle.aspx?ID=152

Tip 7: How to loop through all the rows in all the pages of a GridView

One simple way to loop through all the rows in all the pages of a GridView is to access its DataSource. In this example, we will loop through the SQLDataSource to retrieve all the rows in a GridView and access its cell value. You can modify the logic depending on the type of controls you have added to the GridView

protected void Button1_Click(object sender, EventArgs e)

{

DataSourceSelectArguments dsaArgs = new DataSourceSelectArguments();

DataView view = (DataView)SqlDataSource1.Select(dsaArgs);

DataTable dt = view.ToTable();

for (int i = 0; i < dt.Rows.Count; i++)

{

for (int j = 0; j < dt.Columns.Count; j++)

{

string s = dt.Rows[i][j].ToString();

}

VB.NET

Protected Sub Button1_Click(ByVal sender As Object, ByVal e As EventArgs)

Dim dsaArgs As DataSourceSelectArguments = New DataSourceSelectArguments()

Dim view As DataView = CType(SqlDataSource1.Select(dsaArgs), DataView)

Dim dt As DataTable = view.ToTable()

For i As Integer = 0 To dt.Rows.Count - 1

For j As Integer = 0 To dt.Columns.Count - 1

Dim s As String = dt.Rows(i)(j).ToString()

Next j

Next i

End Sub

Well that was a quick overview of some of the most frequently used features of the GridView control. I hope you liked the article and I thank you for viewing it.

Dane's blog

Monday, January 12, 2009

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Tuesday, December 9, 2008

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Monday, November 17, 2008

Javascript and Asp.net

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Wednesday, November 5, 2008

65 Excellent jQuery Resources (tutorials,cheat sheets,ebooks,demos,plugins…)

Thursday, October 23, 2008

GridView Tips and Tricks using ASP.NET – Part III ( Fron dotnetcurry)

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