Introduction:
Here I will explain how to show or display images from database using generic handler ashx in asp.net using c#, vb.net with example or upload images in byte array format and display images from sql server database using generic handler ashx in asp.net gridview using c#, vb.net.
Description:
In previous articles I explained jQuery upload multiple files using handler file in asp.net, display images from database path in asp.net gridview, upload & download files from database in asp.net, save images in folder and path in database display it in asp.net gridview, gridview examples in asp.net, Delete multiple rows in gridview using checkbox in asp.net and many articles relating to gridview, asp.net, c#,vb.net and jQuery. Now I will explain how to save and display images from sql server database in asp.net gridview control using c#, vb.net with example.
In previous articles I explained jQuery upload multiple files using handler file in asp.net, display images from database path in asp.net gridview, upload & download files from database in asp.net, save images in folder and path in database display it in asp.net gridview, gridview examples in asp.net, Delete multiple rows in gridview using checkbox in asp.net and many articles relating to gridview, asp.net, c#,vb.net and jQuery. Now I will explain how to save and display images from sql server database in asp.net gridview control using c#, vb.net with example.
Before
implement this example first design one table imagedetails in your database as
shown below
Column Name
|
Data Type
|
Allow Nulls
|
imageid
|
Int(IDENTITY=TRUE)
|
NO
|
imagename
|
varchar(50)
|
Yes
|
imagedata
|
varbinary(max)
|
Yes
|
Once
table created in database that would be like as shown below
 |
Now
open your aspx page and write the code like as shown below
<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1">
<title>Display images from sql
server database in asp.net gridview control</title>
<style type="text/css">
.GridviewDiv {font-size: 100%; font-family: 'Lucida
Grande', 'Lucida Sans Unicode', Verdana, Arial, Helevetica, sans-serif;
color: #303933;}
.headerstyle
{
color:#FFFFFF;border-right-color:#abb079;border-bottom-color:#abb079;background-color:
#df5015;padding:0.5em 0.5em 0.5em 0.5em;text-align:center;
}
</style>
</head>
<body>
<form id="form1"
runat="server">
<div>
<asp:FileUpload ID="fileUpload1"
runat="server"
/><br
/>
<asp:Button ID="btnUpload"
runat="server"
Text="Upload"
onclick="btnUpload_Click"
/>
</div>
<div class="GridviewDiv">
<asp:GridView ID="gvImages"
CssClass="Gridview"
runat="server"
AutoGenerateColumns="False">
<HeaderStyle CssClass="headerstyle"
/>
<Columns>
<asp:BoundField HeaderText =
"Image Name" DataField="imagename"
/>
<asp:TemplateField HeaderText="Image">
<ItemTemplate>
<asp:Image ID="Image1"
runat="server"
ImageUrl='<%# "ImageHandler.ashx?ImID="+
Eval("imageid") %>' Height="150px" Width="150px"/>
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
</div>
</form>
</body>
</html>
|
Now add following namespaces in codebehind file
C#
Code
using System;
using System.Data.SqlClient;
using System.IO;
using
System.Web.UI.WebControls;
using System.Web;
|
After completion of adding namespaces you need to write the
code like as shown below
string strCon = "Data Source=Suresh;Integrated
Security=true;Initial Catalog=MySampleDB";
protected void Page_Load(object
sender, EventArgs e)
{
if (!IsPostBack)
{
BindGridviewData();
}
}
// Bind Gridview Data
private void BindGridviewData()
{
using (SqlConnection con = new
SqlConnection(strCon))
{
using (SqlCommand cmd = new
SqlCommand())
{
cmd.CommandText = "select
imageid,imagename from imagedetails";
cmd.Connection = con;
con.Open();
gvImages.DataSource = cmd.ExecuteReader();
gvImages.DataBind();
con.Close();
}
}
}
// Save files to Folder and files path in database
protected void btnUpload_Click(object
sender, EventArgs e)
{
//Condition to check if the file uploaded or not
if (fileUpload1.HasFile)
{
int length =
fileUpload1.PostedFile.ContentLength;
byte[] imgbyte = new byte[length];
HttpPostedFile img =
fileUpload1.PostedFile;
//set the binary data
img.InputStream.Read(imgbyte, 0, length);
string filename = Path.GetFileName(fileUpload1.PostedFile.FileName);
using (SqlConnection con = new
SqlConnection(strCon))
{
using (SqlCommand cmd = new
SqlCommand())
{
cmd.CommandText = "insert into
imagedetails(imagename,imagedata) values(@Name,@Data)";
cmd.Parameters.AddWithValue("@Name",
filename);
cmd.Parameters.AddWithValue("@Data",
imgbyte);
cmd.Connection = con;
con.Open();
cmd.ExecuteNonQuery();
con.Close();
BindGridviewData();
}
}
}
}
|
VB.NET
Code
Imports System.Data.SqlClient
Imports System.IO
Imports
System.Web.UI.WebControls
Imports System.Web
Partial Class VBCode
Inherits System.Web.UI.Page
Private strCon As String = "Data Source=Suresh;Integrated
Security=true;Initial Catalog=MySampleDB"
Protected Sub Page_Load(ByVal
sender As Object,
ByVal e As EventArgs) Handles
Me.Load
If Not
IsPostBack Then
BindGridviewData()
End If
End Sub
' Bind Gridview Data
Private Sub BindGridviewData()
Using con As New SqlConnection(strCon)
Using cmd As New SqlCommand()
cmd.CommandText = "select
imageid,imagename from imagedetails"
cmd.Connection = con
con.Open()
gvImages.DataSource = cmd.ExecuteReader()
gvImages.DataBind()
con.Close()
End Using
End Using
End Sub
' Save files to Folder and files path in database
Protected Sub btnUpload_Click(ByVal
sender As Object,
ByVal e As EventArgs)
'Condition to check if the file uploaded or not
If fileUpload1.HasFile Then
Dim length As Integer =
fileUpload1.PostedFile.ContentLength
Dim imgbyte As Byte() = New Byte(length -
1) {}
Dim img As HttpPostedFile
= fileUpload1.PostedFile
'set the binary data
img.InputStream.Read(imgbyte, 0, length)
Dim filename As String = Path.GetFileName(fileUpload1.PostedFile.FileName)
Using con As New SqlConnection(strCon)
Using cmd As New SqlCommand()
cmd.CommandText = "insert into
imagedetails(imagename,imagedata) values(@Name,@Data)"
cmd.Parameters.AddWithValue("@Name",
filename)
cmd.Parameters.AddWithValue("@Data",
imgbyte)
cmd.Connection = con
con.Open()
cmd.ExecuteNonQuery()
con.Close()
BindGridviewData()
End Using
End Using
End If
End Sub
End Class
|
If you observe above gridview TemplateField code in aspx page we
are fetching images using Handler file ImageHandler.ashx
because we are saving images in binary format. By using HTTPHandler we can easily get binary data and display it in our
application.
Here HTTPHandler
is a simple class that allows you to process a request and return a response to
the browser. Simply we can say that a Handler is responsible for fulfilling
requests from the browser. It can handle only one request at a time, which in
turn gives high performance.
To add handler file Right Click on your project Ã
select Add New Item à select Handler file Ã
give name as ImageHandler.ashx like as shown in following image and click ok
 |
Now open your ImageHandler.ashx
file and write the following code
C#
Code
using System;
using System.Web;
using System.Data.SqlClient;
public class ImageHandler
: IHttpHandler {
public void ProcessRequest (HttpContext
context) {
string imageid =
context.Request.QueryString["ImID"];
SqlConnection con = new SqlConnection("Data Source=Suresh;Integrated
Security=true;Initial Catalog=MySampleDB");
con.Open();
SqlCommand cmd = new SqlCommand("select imagedata from imagedetails where
imageid=" + imageid, con);
SqlDataReader dr =
cmd.ExecuteReader();
dr.Read();
context.Response.BinaryWrite((byte[])dr[0]);
con.Close();
context.Response.End();
}
public bool IsReusable {
get {
return false;
}
}
}
|
VB.NET
Code
Imports System.Web
Imports System.Data.SqlClient
Public Class Handler : Implements IHttpHandler
Public Sub ProcessRequest(ByVal
context As HttpContext)
Implements IHttpHandler.ProcessRequest
Dim imageid As String =
context.Request.QueryString("ImID")
Dim con As New SqlConnection("Data
Source=Suresh;Integrated Security=true;Initial Catalog=MySampleDB")
con.Open()
Dim cmd As New SqlCommand(Convert.ToString("select imagedata from imagedetails where
imageid=") & imageid, con)
Dim dr As SqlDataReader
= cmd.ExecuteReader()
dr.Read()
context.Response.BinaryWrite(DirectCast(dr(0),
Byte()))
con.Close()
context.Response.[End]()
End Sub
Public ReadOnly Property
IsReusable() As Boolean
Implements IHttpHandler.IsReusable
Get
Return False
End Get
End Property
End Class
|
Now run your application and check output that would be
like as shown in following output
Demo
 |
|
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