Dot Net Code Snippets

Good Morning after a month I spend the time to post the small tips who already known but i would like to share this post which everyone come to know.

Question :  how to check the specific field in the row has contain null or value.

Normally we used to get the data from the DB using specific id for ex: get the specific user details using his userid. So it will return that row value. In that row some field may contain NULL value.

Here is the code to check the particular field contains value or null.

In my case I am getting the row from Database and assigned to the Datarow like this

Dim dr as DataRow

dr = ds.Tables(0).Rows(0)

if (dr.IsNull("fieldname")) then
' if the field contain null do the manipulation here
else
' the field cotains some value.
End if 

< img src="Dynamic-imagename" onerror="this.src='../images/NoImageFound.jpg'" .. / > 

Hi Good Evening Techies.

 <ajax:ScriptManager ID="ScriptManager1" runat="server">
        </ajax:ScriptManager>

<asp:HyperLink ID="Hyperlink1" runat="server" Text="Session Mode"               NavigateUrl="~/Description.aspx"></asp:HyperLink>

 <ajaxToolkit:HoverMenuExtender ID="hme2" runat="Server" TargetControlID="Hyperlink1"
            PopupControlID="Panel1" PopupPosition="Center" OffsetX="-25" OffsetY="15"
/>

<asp:Panel ID="Panel1" runat="server" Width="600px">
            <asp:DataList ID="Dtl_Unit" CellPadding="1" CellSpacing="1"
ShowHeader="False" BorderWidth="0px"
                runat="server" DataKeyField="ServicesSubId" DataSourceID="Sqd_Unit" 

RepeatColumns="5">
                <ItemTemplate>
                    <table border="0">
                        <tr>
                            <td>
                                     <asp:HyperLink ID="Hyperlink2"  runat="server" 

NavigateUrl='<%#"Description.aspx?SId="+Eval("sessionmodeID") %>'
Text='<%#Eval("sessionmodeName")%>'></asp:HyperLink>
                            </td>

                        </tr>
                    </table>
                </ItemTemplate>
                <ItemStyle BorderWidth="0px"  />
            </asp:DataList>
            <asp:SqlDataSource ID="Sqd_Unit" runat="server" ConnectionString="<%$ 

ConnectionStrings:ConnectionString %>"
                SelectCommand="SELECT [sessionmodeID], [sessionmodeName] FROM 

[SessionTable]">
            </asp:SqlDataSource>
        </asp:Panel>

When i faced this issue

if(!IsPostback)

{
//Bind the Gridview Databind
}

// here getting the 15 Minutes, if you want the time difference you use it here..ie: to // update the your page at regular intervals.
TimeSpan onlineSpan = new TimeSpan(0,15,0);
// here i minus the 15 Minutes from the Current Datetime and pass it as a parameter
            DateTime compareTime = DateTime.Now.Subtract(onlineSpan);
            using (SqlCommand cmd = new SqlCommand("SELECT users.username from users where users.LastActivityDate > @CompareDate ", con))
{
            cmd.Parameters.Add("@CompareDate", SqlDbType.DateTime).Value = compareTime;
            using(SqlDataAdapter adap = new SqlDataAdapter())
            {
            adap.SelectCommand = cmd;
            }

}          
            DataTable dt = new DataTable();
            adap.Fill(dt);
            OnlineuserList_GridView.DataSource = dt;
            OnlineuserList_GridView.DataBind();

Good Day to All.

<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns ="True" OnRowDataBound="GridView1_RowDataBound">
        <Columns >
        <asp:TemplateField >
        <ItemTemplate >
        <table >
        <tr>
        <td>
            <asp:PlaceHolder ID="PlaceHolder1" runat="server"></asp:PlaceHolder>
        </td>
        <br />
        <td>
         <asp:PlaceHolder ID="PlaceHolder2" runat="server"></asp:PlaceHolder>
        </td>
        <br />
        
        <td>
         <asp:PlaceHolder ID="PlaceHolder3" runat="server"></asp:PlaceHolder>
        </td>
        </tr>
        </table>
        </ItemTemplate>
        </asp:TemplateField>
        </Columns>
        </asp:GridView>

   <asp:Button ID="Button1" runat="server" Text="Get Value" OnClick="Button1_Click"  />

private void BindArraylist()
    {
        List<string> bindG = new List<string>() ;
        bindG .Add ("Mani");
        bindG .Add ("Shivaram");
        bindG .Add ("Gopi");
        bindG.Add ("Venu");
        GridView1 .DataSource = bindG ;
        GridView1 .DataBind ();
     
    }
//page_OnLoad

 if (!Page.IsPostBack)
        {
            
            BindArraylist();
        }

//On Row databound we are creation a dynamic dropdownlist, by adding some items and added to the Placholder Container

 protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
    {
        if (e.Row.RowType == DataControlRowType.DataRow)
        {
            PlaceHolder p1 = new PlaceHolder();
            PlaceHolder p2 = new PlaceHolder();
            PlaceHolder p3 = new PlaceHolder();

            p1 = (PlaceHolder)e.Row.FindControl("PlaceHolder1");
            p2 = (PlaceHolder)e.Row.FindControl("PlaceHolder2");
            p3 = (PlaceHolder)e.Row.FindControl("PlaceHolder3");

            DropDownList d1 = new DropDownList();
            DropDownList d2 = new DropDownList();
            DropDownList d3 = new DropDownList();
            d1.ID = "d1";
            d1.Items.Add("123");
            d1.Items.Add("00");
            d1.Items.Add("dfgdf");
            d2.ID = "d2";
            d2.Items.Add("34f");
            d2.Items.Add("h456");
            d2.Items.Add("ngfy3e35");
            d3.ID = "d3";
            d3.Items.Add("3478");
            d3.Items.Add("0fghdj0");
            d3.Items.Add("2d43g5gh5");

            p1.Controls.Add(d1);
            p2.Controls.Add(d2);
            p3.Controls.Add(d3);
      }
}

protected void Button1_Click(object sender, EventArgs e)
    {
        BindArraylist();
        foreach (GridViewRow row in GridView1.Rows)
        {
        
            DropDownList d1 = new DropDownList();
            DropDownList d2 = new DropDownList();
            DropDownList d3 = new DropDownList();

            d1 = (DropDownList)row.FindControl("d1");
            d2 = (DropDownList)row.FindControl("d2");
            d3 = (DropDownList)row.FindControl("d3");
            //txtValues.Add(d1.SelectedIndex.ToString());
  
            Response.Write(d1.SelectedValue.ToString() + "-" + d2.SelectedValue.ToString() + "-" + d3.SelectedValue.ToString());
        }
    }

When i was worked with Ajax with timer Control i have the task ie: updating the some control inside the UpdatePanel ie: I am refreshing or call the method  at regular intervals. That time i got this error

 Sys.WebForms.PageRequestManagerServerErrorException ... 404 not found

This error occurs only when the page is idle for 1 min or more than 1 min, so i googled to get the solution for this issue. there is number of solution available according the problem and at which situation you are using.

< asp:ScriptManager ID="ScriptManager1" runat="server"   EnablePartialRendering="false" />

<add key="Set_Css" 

value="App_Themes/Default/Css1.css,App_Themes/Default/Css2.css"/>
  <add key="Set_Javascript" 
value="Javascripts/Js1.js,Javascripts/Js2.js,

http://ajax.googleapis.com/ajax/libs/jquery/1.2.6/jquery.min.js"/>

<link   type="text/css" 
            rel="Stylesheet" 
            href="HttpCombiner.ashx?s=Set_Css&t=text/css&v=1" />

    <script     
        type="text/javascript" 
        src="HttpCombiner.ashx?s=Set_Javascript&t=type/javascript&v=2" >
    </script>

Good Evening to All.
Here I am going to cover how to compress the .aspx pages.
so there are no.of ways to compress the pages in asp.net
1) using IIS.
2) using Code ie: through HTTPCompress.dll i got the source code from codeproject.com.
so i am going to share with you.
There are two type of Compression ie: Deflate , GZIP. here i am going to use GZIP compression to compress the asp.net pages.
First Place the DLL file ie::HTTPCompress.dll to the Bin folder of your project.
Then you have to include some tag on web.config file

<configsections>
  <sectiongroup name="Flanders">
   <section name="HttpCompress" type="Flanders.Library.Modules.HttpCompress.Configuration, HttpCompress">
  </section>
 </sectiongroup>
<flanders>
  <httpcompress compressiontype="GZip">
   <excludedpaths>
    <add path="NoCompression.aspx">
   </add>
   <excludedmimetypes>
    <add mime="image/jpeg">
   </add>
  </excludedmimetypes></excludedpaths>
</httpcompress>
</flanders>

</configsections>

<excludedmimetypes>
  <add mime="image/jpeg">
  <add mime="image/jpg">
  <add mime="image/png">
  <add mime="image/gif">
</add>
</add>
</add>
</add>
</excludedmimetypes>

<httpmodules>
   <add> name="HttpCompressModule" type="Flanders.Library.Modules.HttpCompress.HttpModule,HttpCompress"/>
 </add>
</httpmodules>

Some members asked this question on forums. Here is the Solution to overcome this issue.

When i am going to compress the .aspx pages using HTTPCompression, the postback will not works. Because it also compressing the Scripresource.axd, webresource.axd file.

To make the postback works in your project you do not compress the above two files, by adding these code.

Solution:

........,

<httpcompress compressiontype="GZip">
 <excludedpaths>
 <add path="scriptresource.axd">
 <add path="webresource.axd">
</add>
</add>
</excludedpaths></httpcompress>

..,
<excludedmimetypes>
 <add mime="image/jpeg">
 </add>
 </excludedmimetypes>

I saw the question repeatedly asking on forums ie: how to convert the String to datetime.

even if someone give solution still the problems exists..,

Error: String is not recognized as a valid DateTime.

Here i am giving the solution to overcome the problem.

First make sure whether you entered is a valid date or not because User may enter alphabets, special symbols etc.. so in order to avoid that , I have to validate the textbox. Here i am using the Regex to to validate the date.

This is my Article to vaildate date using Regex

try
{
 string sDate ="06/05/2010";
// this the regex to match the date ie: dd/MM/yyyy
 string _dateExpression = @"^((0[1-9]|[12][0-9]|3[01])[- /.](0[1-9]|1[012])[- /.](?:19|20)\d\d)$";
 Regex chkDate = new Regex(_dateExpression);
 if ((chkDate.IsMatch(sDate))
 {
 // so if the date is valid and its matched you can store the date on DB or do some manipulatio.
 }
 else
 {
 // show invalid date
 }
}
 catch (System.FormatException ex)
 {
 // show invalid date
 }
catch(Exception ex1)
{
throw;
}

DateTime sDate = new DateTime();

sDate = DateTime.Today; //  Here i am getting like this 5/6/2010

// So i want this format 05/06/2010  - for this i am using Format to Convert the Date as i Want.

string gDate = String.Format("{0:dd-MM-yyyy}", sDate);

Good Morning to Everybody this is my First article.
Now i am going to see how to send email Asynchronously, actually we send email normally using asp.net Example check here..
Send Email Using ASP.NET

By default smtpClient has one method called SendAsync to send an email ansynchronously. so if you sending an email normally it will take some time for each mail sent. But if you send an email Asynchronously it will not wait for each mail sent it will do the other process , while mail sending is done at background process.
So Here is the code.

//creating mail message object
 MailMessage mailMessage = new MailMessage();
 mailMessage.From = new MailAddress("venkat@gmail.com");
 mailMessage.To.Add(new MailAddress("msdotnettechies@gmail.com"));
 mailMessage.CC.Add(new MailAddress("user1@gmail.com"));
 mailMessage.Bcc.Add(new MailAddress("user2@gmail.com"));
 mailMessage.Subject = "Email Checking Asynchronously";
 mailMessage.Body = "Email test asynchronous";
 mailMessage.IsBodyHtml = true;//to send mail in html or not

 SmtpClient smtpClient = new SmtpClient();//portno here
 smtpClient.Host = "smtp.gmail.com";
 smtpClient.EnableSsl = true ; //True or False depends on SSL Require or not
 smtpClient.Credentials = new NetworkCredential("yourGmail@gmail.com", "yourpassword");
 //smtpClient.UseDefaultCredentials = true; //true or false depends on you want to default credentials or not
 Object mailState = mailMessage;

 //this code adds event handler to notify that mail is sent or not
 smtpClient.SendCompleted += new SendCompletedEventHandler(smtpClient_SendCompleted);
 try
 {
 smtpClient.SendAsync(mailMessage, mailState);
 }
 catch (Exception ex)
 {
 Response.Write(ex.Message);
 Response.Write(ex.StackTrace);
 }

// this is the event called on main method
void smtpClient_SendCompleted(object sender, System.ComponentModel.AsyncCompletedEventArgs e)
 {
 MailMessage mailMessage = e.UserState as MailMessage;
 if (e.Cancelled || e.Error != null)
 {

 Response.Write(e.Error.Message);
 Response.Write(e.Error.StackTrace);
 }
 else
 {
 Response.Write("Email sent successfully");
 }
 } 

 <meta http-equiv="PRAGMA" value="NO-CACHE"></meta>
<meta content="Mon, 01 Jan 1990 12:00:00 GMT" http-equiv="Expires"></meta>