Maintain Scroll Position On After Postback in Asp.Net

Maintain Scroll Position on or After Postback in Asp.Net 2.0 3.5.

In this example i'm explaining different methods of maintaining scroll position on/after postback in asp.net 2.0,3.5 web pages or applications.

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Forms Authentication In Asp.Net

In examples below i'm explaining how to use forms authentication in Asp.Net and forms authentication tickets in Asp.net.

Forms Authentication In Asp.Net 2.0 and 3.5

Forms Authentication in ASP.NET is technique to decide how users can access your web application.

Using froms authentication we can decide certain users can access only certain pages or we can control the anonymous access, we can implement folder level access and access based on roles.

we can manage the access through web.config file or folder level access and through multiple web.config files using forms authentication.

Forms Authentication Ticket In Asp.Net 2.0 And 3.5

In this article i am going to describe how to implement Forms authentication tickets and manage user roles based access in ASP.NET using C# and multiple web.config files

Bypass Forms Authentication Or Skip Authorization

Some readers ask me how to skip or bypass forms authentication or Authorization for selected pages in asp.net or a scenario where only few pages on site needs user to log in rest can be accessed without login.

Select Find Nth Highest Salary Record In Sql Server

Find or Select nth highest salary record in ms sql

This is most frequentky asked question how to select or get nth highest record or nth row/record from any column of sql table.

for example select get or fetch 2nd (second highest) or nth highest salary of employee or 10th highest record from the table.

There are various ways to achieve this result, i've mentioned few here.

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Asp.Net QueryString Example

In this post i am explaining how to use querystrings.

Example url with querystring can be something similar like this

http://yahoo.com/defauld.aspx?variable1=value1&variable2=value2

Suppose we have a textbox txtData and we want it's value on other page
than in code behind we would write in click event of btnGo

1private void btnGO_Click(object sender, System.EventArgs e)

2{

3Response.Redirect("Default2.aspx?Value=" +

4txtData.Text);

5}

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Pass Crystal Report Parameters Programmatically

Pass crystal report parameters programmatically in Asp.Net 2.0,3.5.

In this post i am explaining how to pass parameters to crystal reports programmatically in code behind of asp.net web page.

For this i am using northwind database and products table.

I have put one text box on the page and report will display details of product based on product id entered by user.




To know how to create crystal report in Asp.Net .

If u want to know how to create crystal reports with parameters in winforms or windows application then read this.

Open crystal report in design view, right click on it and select Field Explorer

Now select Parameter Fields and select new to add new parameter to report.

Name it as ProductID and remember it.

Now click on Special Fields in Field Explorer and select Record Selection Formula.

Select is equal to and {?ProductID} from the dropdowns and click on OK.

Click on smart tag of reportviewer control and uncheck Database logon prompting and parameter prompting as we will provide these info in code behind.

HTML markup of aspx page

<form id="form1" runat="server">
    <table class="style1">
        <tr>
            <td>
                Enter Product ID :
            </td>
            <td>
                <asp:TextBox ID="txtProductID" runat="server">
                </asp:TextBox>
                </td>
            <td>
                <asp:Button ID="btnReport" runat="server" 
                            Text="Show Report" 
                            onclick="btnReport_Click" 
                            Width="108px" />
                </td>
        </tr>
    </table>
    <br />
    <CR:CrystalReportViewer ID="CrystalReportViewer1" runat="server" 
        AutoDataBind="True" EnableDatabaseLogonPrompt="False" 
        EnableParameterPrompt="False" Height="1039px" 
        ReportSourceID="CrystalReportSource1" 
        ReuseParameterValuesOnRefresh="True" 
        Width="901px" DisplayGroupTree="False" />
    <CR:CrystalReportSource ID="CrystalReportSource1" runat="server">
        <Report FileName="CrystalReport.rpt">
        </Report>
    </CR:CrystalReportSource>
    </form>

Now go to code behind of the page and add below mentioned namespace for crystal reports.

1using CrystalDecisions.Shared;

2using CrystalDecisions.CrystalReports.Engine;

Write this code in Page_Load event of the page

1protected void Page_Load(object sender, EventArgs e)

2    {

3        if (Page.IsPostBack) CrystalReportViewer1.Visible = true;

4        else

5            CrystalReportViewer1.Visible = false;

6    }

Generate click event for button to shaow report and write this code.

01protected void btnReport_Click(object sender, EventArgs e)

02    {   //Create report document

03        ReportDocument crystalReport = new ReportDocument();

04 

05        //Load crystal report made in design view

06        crystalReport.Load(Server.MapPath("CrystalReport.rpt"));

07 

08        //Set DataBase Login Info

09        crystalReport.SetDatabaseLogon

10            ("amitjain", "password", @"AMITJAIN\SQL", "Northwind");

11 

12        //Provide parameter values

13        crystalReport.SetParameterValue("ProductID", txtProductID.Text);

14        CrystalReportViewer1.ReportSource = crystalReport;

15    }

Build the solution and run.

Hide Show Div Using JQuery Asp.Net

Show hide div using jquery example in asp.net.

So many times while developing web application we need to show or hide div or other html elements based on user interaction as shown in picture.

we can do this with ease using JQuery.

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Export GridView To Excel ASP.NET

Export GridView to Excel in asp.net 2.0,3.5 using C# and VB.NET

In this post i am going to explian how to export gridview to ms excel using C# and VB.NET.

For this i have used northwind database to populate gridview. To learn how to populate gridview .







After populating gridview we have to export gridview to excel on click of button placed in page.

For this we can simply write this code in click event of button

01Response.ClearContent();

02 

03        Response.AddHeader("content-disposition", "attachment; filename=GridViewToExcel.xls");

04 

05        Response.ContentType = "application/excel";

06 

07        StringWriter sWriter = new StringWriter();

08 

09        HtmlTextWriter hTextWriter = new HtmlTextWriter(sWriter);

10 

11        GridView1.RenderControl(hTextWriter);

12 

13        Response.Write(sWriter.ToString());

14 

15        Response.End();

But when we click on button to export gridview to excel we get this httpexception error.

to get past this either we can write this method in code behind.

1public override void VerifyRenderingInServerForm(Control control)

2{

3}

or we can add a html form and render it after adding gridview in it, i'll be using this.

If we have enabled paging in gridview or gridview contains controls like linkbutton, dropdowns or checkboxes etc then we get this error.

we can fix this error by setting event validation property to false in page directive.

1<%@ Page Language="C#" AutoEventWireup="true"  <b>EnableEventValidation="false" </b>CodeFile="Default.aspx.cs" Inherits="_Default" %>

When we export gridview containg controls then hyperlinks or other controls are not desireable in excel sheet, we need to display their display text insted for this we need to write a method to remove controls and display their respective text property as mentioned below.

01private void ChangeControlsToValue(Control gridView)

02    {

03        Literal literal = new Literal();

04 

05        for (int i = 0; i < gridView.Controls.Count; i++)

06        {

07            if (gridView.Controls[i].GetType() == typeof(LinkButton))

08            {

09 

10                literal.Text = (gridView.Controls[i] as LinkButton).Text;

11                gridView.Controls.Remove(gridView.Controls[i]);

12                gridView.Controls.AddAt(i,literal);

13            }

14            else if (gridView.Controls[i].GetType() == typeof(DropDownList))

15            {

16                literal.Text = (gridView.Controls[i] as DropDownList).SelectedItem.Text;

17 

18                gridView.Controls.Remove(gridView.Controls[i]);

19 

20                gridView.Controls.AddAt(i,literal);

21 

22            }

23            else if (gridView.Controls[i].GetType() == typeof(CheckBox))

24            {

25                literal.Text = (gridView.Controls[i] as CheckBox).Checked ? "True" : "False";

26                gridView.Controls.Remove(gridView.Controls[i]);

27                gridView.Controls.AddAt(i,literal);

28            }

29            if (gridView.Controls[i].HasControls())

30            {

31 

32                ChangeControlsToValue(gridView.Controls[i]);

33 

34            }

35 

36        }

37 

38    }

Complete HTML source of page look like

<asp:GridView ID="GridView1" runat="server" AllowPaging="True" 
              DataSourceID="sqlDataSourceGridView" 
              AutoGenerateColumns="False"
              CssClass="GridViewStyle" 
              GridLines="None" Width="650px" 
              ShowHeader="False">
<Columns>
<asp:TemplateField HeaderText="Customer ID" ItemStyle-Width="75px">
<ItemTemplate>
<asp:LinkButton ID="lButton" runat="server" Text='<%#Eval("CustomerID") %>' 
                PostBackUrl="~/Default.aspx">
</asp:LinkButton>
</ItemTemplate>
<ItemStyle Width="75px"></ItemStyle>
</asp:TemplateField>
<asp:BoundField DataField="CompanyName" HeaderText="Company" 
                ItemStyle-Width="200px" >
<ItemStyle Width="200px"></ItemStyle>
</asp:BoundField>
<asp:BoundField DataField="ContactName" HeaderText="Name" 
                ItemStyle-Width="125px">
<ItemStyle Width="125px"></ItemStyle>
</asp:BoundField>
<asp:BoundField DataField="City" HeaderText="city" ItemStyle-Width="125px" >
<ItemStyle Width="125px"></ItemStyle>
</asp:BoundField>
<asp:BoundField DataField="Country" HeaderText="Country" 
                ItemStyle-Width="125px" >
<ItemStyle Width="125px"></ItemStyle>
</asp:BoundField>
</Columns>
<RowStyle CssClass="RowStyle" />
<PagerStyle CssClass="PagerStyle" />
<SelectedRowStyle CssClass="SelectedRowStyle" />
<HeaderStyle CssClass="HeaderStyle" />
<AlternatingRowStyle CssClass="AltRowStyle" />
</asp:GridView>

<asp:SqlDataSource ID="sqlDataSourceGridView" runat="server" 
ConnectionString="<%$ ConnectionStrings:northWindConnectionString %>" 
SelectCommand="SELECT [CustomerID], [CompanyName], [ContactName], 
               [City], [Country] FROM [Customers]">
</asp:SqlDataSource>

<table align="left" class="style1">
<tr>
<td class="style2">
<asp:RadioButtonList ID="RadioButtonList1" runat="server" AutoPostBack="True" 
                     RepeatDirection="Horizontal" RepeatLayout="Flow">
<asp:ListItem Value="0">All Pages</asp:ListItem>
</asp:RadioButtonList>
</td>
<td>
<asp:Button ID="btnExportToExcel" runat="server" Text="Export To Excel" 
            Width="215px" onclick="btnExportToExcel_Click"/>
</td>
</tr>
</table>

C# Code

01protected void btnExportToExcel_Click(object sender, EventArgs e)

02    {

03        if (RadioButtonList1.SelectedIndex == 0)

04        {

05            GridView1.ShowHeader = true;

06            GridView1.GridLines = GridLines.Both;

07            GridView1.AllowPaging = false;

08            GridView1.DataBind();

09        }

10        else

11        {

12            GridView1.ShowHeader = true;

13            GridView1.GridLines = GridLines.Both;

14            GridView1.PagerSettings.Visible = false;

15            GridView1.DataBind();

16        }

17 

18        ChangeControlsToValue(GridView1);

19        Response.ClearContent();

20 

21        Response.AddHeader("content-disposition", "attachment; filename=GridViewToExcel.xls");

22 

23        Response.ContentType = "application/excel";

24 

25        StringWriter sWriter = new StringWriter();

26 

27        HtmlTextWriter hTextWriter = new HtmlTextWriter(sWriter);

28 

29        HtmlForm hForm = new HtmlForm();

30 

31        GridView1.Parent.Controls.Add(hForm);

32 

33        hForm.Attributes["runat"] = "server";

34 

35        hForm.Controls.Add(GridView1);

36 

37        hForm.RenderControl(hTextWriter);

38 

39        Response.Write(sWriter.ToString());

40 

41        Response.End();

42    }

43 

44    private void ChangeControlsToValue(Control gridView)

45    {

46        Literal literal = new Literal();

47 

48        for (int i = 0; i < gridView.Controls.Count; i++)

49        {

50            if (gridView.Controls[i].GetType() == typeof(LinkButton))

51            {

52 

53                literal.Text = (gridView.Controls[i] as LinkButton).Text;

54                gridView.Controls.Remove(gridView.Controls[i]);

55                gridView.Controls.AddAt(i,literal);

56            }

57            else if (gridView.Controls[i].GetType() == typeof(DropDownList))

58            {

59                literal.Text = (gridView.Controls[i] as DropDownList).SelectedItem.Text;

60 

61                gridView.Controls.Remove(gridView.Controls[i]);

62 

63                gridView.Controls.AddAt(i,literal);

64 

65            }

66            else if (gridView.Controls[i].GetType() == typeof(CheckBox))

67            {

68                literal.Text = (gridView.Controls[i] as CheckBox).Checked ? "True" : "False";

69                gridView.Controls.Remove(gridView.Controls[i]);

70                gridView.Controls.AddAt(i,literal);

71            }

72            if (gridView.Controls[i].HasControls())

73            {

74 

75                ChangeControlsToValue(gridView.Controls[i]);

76 

77            }

78 

79        }

80 

81    }

This is how excel sheet will look like. Hope this helps.