Move to Top in the page

When ever your web site page size is very high , Users feel time wast for always scrolling up and down directions.
So if you give one step up link its give additional help to your site .for this you can use following code :

<a href="#top">top</a>
href="#top" field will help you move up in that page.

Substring

string  s = "bloger";

//and then i want to remove the last chars "er"


string  g = s.Substring(0, s.Length - 2);


it will give     only  'blog'

to cut  first letter ,we start the sub string  from 1
string  g = s.Substring(1, s.Length - 2);

it will give  'log'  by removing first 2 letters and last 2 letters(chars)

PayPal

For integrating PayPal into your project ,Please go through the following link there you can get the complete code for the PayPal .And also the successive steps to follow how to integrate PayPal to your Application. 

Click here  : PayPal Link

FileUpLoad control

 ASP.NET 2.0 has a FileUpLoad control, which allows developers to drop the control on a page and let it browse a file and upload it on the server.

To create a control, simply drop the FileUpload control from Toolbox to a Web page. The following code adds the FileUpLoad control:

<asp:FileUpLoad id="FileUpLoad1" runat="server" />

To support file upload, we need to add a Button control:

<asp:Button id="UploadBtn" Text="Upload File" OnClick="UploadBtn_Click" runat="server" Width="105px" />

Now on this button click event handler, we need to call SaveAs method of FileUpLoad control, which takes a full path where the file will be uploaded.

protected void UploadBtn_Click(object sender, EventArgs e)
{
if (FileUpLoad1.HasFile)
{

FileUpLoad1.SaveAs(@"C:\anil\" + FileUpLoad1.FileName);
Label1.Text = "File Uploaded: " + FileUpLoad1.FileName ;
}
else
{
Label1.Text = "No File Uploaded.";
}
}

Now if you run the sample, browse a file, and click on Upload File button, the output looks like below Figure .

Figure   FileUpLoad control in action

Restricting File Types

You can restrict the FileUpload control to upload a file type. For example, I wanted to upload images (Jpgs and Gifs) only so I put a validator, which allows Gifs and Jpegs only.

<asp:RegularExpressionValidator
id="FileUpLoadValidator" runat="server"
ErrorMessage="Upload Jpegs and Gifs only."
ValidationExpression="^(([a-zA-Z]:)|(\\{2}\w+)\$?)(\\(\w[\w].*))(.jpg|.JPG|.gif|.GIF)$"
ControlToValidate="FileUpload1">
</asp:RegularExpressionValidator>

Figure 3. Validating images only.

By this code we can upload the the file only up to size of 4MB . If you trying to upload more than 4 MB it shows error  and this is  why? 

The default size of files uploaded by the FileUpload control is 4MB. So if you try to upload the files larger than 4MB, it won't let you do so. To do so, you need to change the default file size in machine.config.comments file for maxRequestLength of httpRuntime tag.  This number is in KB.

<httpRuntime
executionTimeout = "110" [in Seconds][number
maxRequestLength = "4096" [number]
requestLengthDiskThreshold = "80" [number]
useFullyQualifiedRedirectUrl = "false" [true|false]
minFreeThreads = "8" [number]
minLocalRequestFreeThreads = "4" [number]
appRequestQueueLimit = "5000" [number]
enableKernelOutputCache = "true" [true|false]
enableVersionHeader = "true" [true|false]
apartmentThreading = "false" [true|false]
requireRootedSaveAsPath = "true" [true|false]
enable = "true" [true|false]
sendCacheControlHeader = "true" [true|false]
shutdownTimeout = "90" [in Seconds][number]
delayNotificationTimeout = "5" [in Seconds][number]
waitChangeNotification = "0" [number]
maxWaitChangeNotification = "0" [number]
enableHeaderChecking = "true" [true|false]
/>

 

Implementing Cascading DropDownList in ASP.NET GridView

Here’s an approach I followed without using a single line of code. We will be using the Categories and Products table of the Northwind database to show the cascading effect.

Step 1: Open VS 2008. Click File > New > Website. Choose ASP.NET Website ,here ex:C:\VS2008 Projects\ CascadingDropDownInGridView. After typing the location, click OK.

Step 2: Open Default.aspx. Switch to the Design mode of Default.aspx. Open the toolbox (Ctrl+Alt+X) > Data Tab > Drag and drop a SqlDataSource control on to the form. Click on the smart tag or right click SqlDataSource > Show Smart Tag > ‘Configure Data Source’ wizard. Click on ‘New Connection’ to open the ‘Add Connection’. Type your ‘Server Name’ and ‘Select a database Name’ to connect to. Over here, I have used (local) as the ‘ServerName’ and the database I am connecting to, is Northwind. Click on ‘Test Connection’ to make sure that there are no errors while connecting to the server. Click Ok.

Step 3: In the ‘Configure Data Source’, click ‘Next’. An option will be displayed to save the connection string to the configuration file. Select the checkbox ‘Yes, save this connection as:’, type a name for the connectionstring ‘NorthwindConnectionString’ and click Next.

Step 4: In the ‘Configure Select Statement’ > select ‘Specify Columns from Tables or Views’ radiobutton > Select ‘Categories’ table in the Name and choose CategoryID, CateogoryName as columns. Click Next > ‘Test Query’ to preview data > click Finish. The wizard adds a SqlDataSource control to the page as shown below.

<asp:SqlDataSource ID="SqlDataSource1" runat="server"

ConnectionString="<%$ ConnectionStrings:NorthwindConnectionString %>"

SelectCommand="SELECT [CategoryID], [CategoryName] FROM [Categories]">           

</asp:SqlDataSource>

If you check your web.config, the connection string is added as shown below:

<connectionStrings>

      <add name="NorthwindConnectionString" connectionString="Data Source=(local);Initial Catalog=Northwind;Integrated Security=True" providerName="System.Data.SqlClient"/>

</connectionStrings>

Step 5: Now add a GridView control to the page. We will add a BoundField and a TemplateField to display the CategoryID and CategoryName’s respectively. The TemplateField will contain our first dropdownlist displaying CategoryNames.

<form id="form1" runat="server">

<div>

<asp:SqlDataSource ID="SqlDataSource1" runat="server"

ConnectionString="<%$ ConnectionStrings:NorthwindConnectionString %>"

SelectCommand="SELECT [CategoryID], [CategoryName] FROM [Categories]">           

</asp:SqlDataSource>

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

DataKeyNames="CategoryID" DataSourceID="SqlDataSource1">          

<Columns>             

    <asp:BoundField DataField="CategoryID" HeaderText="CategoryID"

        InsertVisible="False" ReadOnly="True" SortExpression="CategoryID" />  

        

    <asp:TemplateField HeaderText="Categories">       

        <ItemTemplate>                  

            <asp:DropDownList ID="ddlCategories" AutoPostBack="true"

            DataTextField="CategoryName" DataValueField="CategoryID"

            DataSourceID="SqlDataSource1" runat="server" AppendDataBoundItems="true"

            SelectedValue='<%# Bind("CategoryID") %>' />

       </ItemTemplate>

    </asp:TemplateField>

</Columns>

</asp:GridView>

</div>

</form>

Note: The SelectedValue='<%# Bind("CategoryID") %>' helps us select the CategoryName in the dropdownlist in accordance with the CategoryID, when the page is first loaded.

Step 6: So far so good. We now have to add the second dropdownlist whose values will be determined at runtime depending on the value selected in the first dropdownlist. In our case, when the user will select CategoryName in the first dropdown, corresponding Products will be displayed in the second dropdown.

Add another Template Field (with a second dropdownlist) in the GridView as well as one more SqlDataSource. This time the SqlDataSource2 will be bound to the ‘Products’ table. Moreover, the ‘SelectCommand’ of the SqlDataSource will accept a parameter, which will be the selected category. Let us see the markup for the same:

<asp:TemplateField HeaderText="Products">       

        <ItemTemplate> 

            <asp:DropDownList ID="ddlProducts"

            DataTextField="ProductName" DataValueField="ProductID"

            DataSourceID="SqlDataSource2" runat="server" />

            <asp:SqlDataSource runat="server" ID="sqlDataSource2"

               ConnectionString="<%$ ConnectionStrings:NorthwindConnectionString %>"

                SelectCommand="SELECT [ProductID], [ProductName], CategoryID FROM [Products]" FilterExpression="CategoryID = '{0}'">

                <FilterParameters>

                <asp:ControlParameter Name="categoryParam" ControlID="ddlCategories"

                     PropertyName="SelectedValue" />

                </FilterParameters>                       

            </asp:SqlDataSource>

         </ItemTemplate>

    </asp:TemplateField>     

Notice the <FilterParameters> element used as a child of the SqlDataSource2. This element is worth observing over here. The <FilterParameters> is a very handy feature of the SqlDataSource control especially when you have a requirement of filtering the results of a query based on a value that is known only at run time. So without making another roundtrip to the server, you can filter out the data that is made available by the SqlDataSource. All you have to do is to create filter expressions that contains parameter placeholders. So for each filter parameter placeholder, you use a parameter element.

In our case, we have created a filter parameter that gets its value from a DropDownList control.

Well that’s all the markup that is required to create cascading dropdownlist in a gridview. Run the application and you can now test the functionality of populating the second dropdownlist based on the selected value of the first dropdownlist. The application will look similar to the image below:

The entire markup is as shown below:

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">

<head runat="server">

    <title>Cascading DropDownList In GridView</title>

</head>

<body>

<form id="form1" runat="server">

<div>

<asp:SqlDataSource ID="SqlDataSource1" runat="server"

ConnectionString="<%$ ConnectionStrings:NorthwindConnectionString %>"

SelectCommand="SELECT [CategoryID], [CategoryName] FROM [Categories]">           

</asp:SqlDataSource>

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

DataKeyNames="CategoryID" DataSourceID="SqlDataSource1">          

<Columns>             

    <asp:BoundField DataField="CategoryID" HeaderText="CategoryID"

        InsertVisible="False" ReadOnly="True" SortExpression="CategoryID" />  

        

    <asp:TemplateField HeaderText="Categories">       

        <ItemTemplate>                  

            <asp:DropDownList ID="ddlCategories" AutoPostBack="true"

            DataTextField="CategoryName" DataValueField="CategoryID"

            DataSourceID="SqlDataSource1" runat="server" AppendDataBoundItems="true"

            SelectedValue='<%# Bind("CategoryID") %>' />

       </ItemTemplate>

    </asp:TemplateField>

       

    <asp:TemplateField HeaderText="Products">       

        <ItemTemplate> 

            <asp:DropDownList ID="ddlProducts"

            DataTextField="ProductName" DataValueField="ProductID"

            DataSourceID="SqlDataSource2" runat="server" />

            <asp:SqlDataSource runat="server" ID="sqlDataSource2"

               ConnectionString="<%$ ConnectionStrings:NorthwindConnectionString %>"

                SelectCommand="SELECT [ProductID], [ProductName], CategoryID FROM [Products]"

                FilterExpression="CategoryID = '{0}'">

                <FilterParameters>

                <asp:ControlParameter Name="categoryParam" ControlID="ddlCategories"

                     PropertyName="SelectedValue" />

                </FilterParameters>                       

            </asp:SqlDataSource>

         </ItemTemplate>

    </asp:TemplateField>     

</Columns>

</asp:GridView>

</div>

</form>

</body>

</html>