Code for displaying columns of the gridview based on the columns checked in the Listbox.

Here is the code for displaying columns of the gridview based on the columns checked in the Listbox. This will by default display one column in the gridview and one checkbox ticked in checkbox list. On selecting other checkboxes i.e. firstname, last name, age,gender the columns become visible in the gridview.
<div>
<asp:CheckBoxList ID="chkColumns" runat="server">
</asp:CheckBoxList>
<asp:Button ID="btnShow" runat="server" Text="Show" OnClick="btnShow_Click" />
</div>
<a href="javascript:void(0);">Click</a>
<asp:GridView ID="GridView1" AutoGenerateColumns="false" runat="server">
<Columns>
    <asp:BoundField DataField="id" HeaderText="id" />
</Columns>
</asp:GridView>
    public static DataTable dt;// = new DataTable();
    public static ArrayList existing = new ArrayList();
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            createtable();
        }
    }
    private void createtable()
        {
            dt = new DataTable();
            dt.Columns.Add("id");
            dt.Columns.Add("firstname");
            dt.Columns.Add("lastname");
            dt.Columns.Add("age");
            dt.Columns.Add("gender");
            object[] d1 = {"1","a","a1","10","M" };
            object[] d2 = { "2", "b", "b1", "20", "F" };
            object[] d3 = { "3", "c", "c1", "30", "M" };
            object[] d4 = { "4", "d", "d1", "40", "F" };
            dt.Rows.Add(d1);
            dt.Rows.Add(d2);
            dt.Rows.Add(d3);
            dt.Rows.Add(d4);
            GridView1.DataSource = dt;
            GridView1.DataBind();
            bindCheckbox();
            AddVisibleColumnsToArray();
            MarkCheckedInArrayForVisibleColumns();
        }
    private void bindCheckbox()
        {
            chkColumns.DataSource = dt.Columns;
            chkColumns.DataBind();
    }
    private void AddVisibleColumnsToArray()
        {
            GetColumnByDBName(GridView1);
        }
        private void MarkCheckedInArrayForVisibleColumns()
        {
            foreach (ListItem item in chkColumns.Items)
            {
                if (existing.Contains(item.Value))
                    item.Selected = true;
            }
        }
    protected void btnShow_Click(object sender, EventArgs e)
        {
            ArrayList arr =new ArrayList();
            HideGridviewColumns(GridView1,arr);
            foreach (ListItem item in chkColumns.Items)
            {
                if (item.Selected)
                {
                    BoundField b = new BoundField();
                    b.DataField = item.Value;
                    b.HeaderText = item.Value;
                    GridView1.Columns.Add(b);
                }
            }
            GridView1.DataSource = dt;
            GridView1.DataBind();
            AddVisibleColumnsToArray();
            MarkCheckedInArrayForVisibleColumns();
    }
    public void GetColumnByDBName(GridView aGridView)
        {
            existing.Clear();
            System.Web.UI.WebControls.BoundField DataColumn;
   
            for (int Index = 0; Index < aGridView.Columns.Count; Index++)
            {
                DataColumn = aGridView.Columns[Index] as System.Web.UI.WebControls.BoundField;
   
                if (DataColumn != null)
                {
                    if (DataColumn.Visible)
                    {
                        if (!existing.Contains(DataColumn.HeaderText))
                            existing.Add(DataColumn.HeaderText);
                    }
                }
            }
        }
   

Get XML node and node attribute value

XmlDocument webConfig = new XmlDocument();
        webConfig.Load(HttpContext.Current.Server.MapPath(@"~\web.config"));
        XmlNode node = webConfig.SelectSingleNode("/configuration/system.web/authentication/forms");
        node.Attributes["timeout"].Value;
        node.Value;

       

Forms Authentication for folders with different login page

Folder Structure:

Admin(Folder)
--Default.aspx
--Login.aspx
--Web.Config
User(Folder)
--Default.aspx
--Login.aspx
--Web.Config
Default.aspx
Login.aspx
Web.Config

The problem is as follows:
If a visitor try to access a page in Admin folder he must be redirected to login page located in Admin folder, here his username and password will be checked in SQL Server table, if authenticated then he will be redirected to Default page and he can access any page in Admin folder, but not the pages in User folder
Note: login page in Admin folder and login page in User folder are different.
Same scenario is for User folder
Solution:Here are the steps to follow:
1. Put following lines in /Admin/Web.config file<configuration>
 <location path="Login.aspx">
  <system.web>
   <authorization>
    <allow users="?"/>
   </authorization>
  </system.web>
</location>
</configuration>
2. Put following lines in /User/Web.config file
<configuration>
 <location path="Login.aspx">
  <system.web>
   <authorization>
    <allow users="?"/>
   </authorization>
  </system.web>
 </location>
</configuration>
3. Put following lines in Web.config file (root). Here Login.aspx page is placed at the root path (Note: loginUrl here is the Login page located on the root path)
<authentication mode="Forms">
 <forms name="login" timeout="120" slidingExpiration="false" loginUrl="Login.aspx"></forms>
</authentication>
<location path="Admin">
 <system.web>
  <authorization>
 <allow roles="Admin"/>
 <deny users="*"/>
  </authorization>
 </system.web>
</location>
  <location path="User">
    <system.web>
      <authorization>   
        <allow  roles="User"/>
        <deny users="*"/>
      </authorization>
    </system.web>
  </location>
  <location path="Default.aspx">
    <system.web>
      <authorization>
        <allow users="*"/>
      </authorization>
    </system.web>
  </location>
4. Put following code only in the Login.aspx page located on the root path
protected void Page_Load(object sender, EventArgs e)
    {
        if (Request.QueryString["ReturnUrl"] != null && Request.QueryString["ReturnUrl"].ToString().Length > 0)
        {
            string returnUrl = Request.QueryString["ReturnUrl"].ToString();
            if (returnUrl.ToLower().Contains("/user/"))
            {
                Response.Redirect(string.Format("~/user/Login.aspx?ReturnUrl={0}", returnUrl));
            }
            if (returnUrl.ToLower().Contains("/admin/"))
            {
                Response.Redirect(string.Format("~/admin/Login.aspx?ReturnUrl={0}", returnUrl));
            }
        }
    }
5. On the Login.aspx page under Admin & User folder do the authentication and put following line at the end of button click.HttpContext.Current.Response.Redirect(FormsAuthentication.GetRedirectUrl(userName, createPersistentCookie));
6. And finally put following code for both signOut and redirect accordingly.
 FormsAuthentication.SignOut();
        Response.Redirect("~/admin/Login.aspx");
        or
        FormsAuthentication.SignOut();
        Response.Redirect("~/user/Login.aspx");

Hoping that this might help!       
 

Hide Gridview column

static public void HideGridviewColumns(GridView aGridView,ArrayList arrColumnName)
    {
        System.Web.UI.WebControls.BoundField DataColumn;
        if (arrColumnName.Count > 0)
        {
            for (int Index = 0; Index < aGridView.Columns.Count; Index++)
            {
                DataColumn = aGridView.Columns[Index] as System.Web.UI.WebControls.BoundField;
                if (DataColumn != null)
                {
                    DataColumn.Visible = !arrColumnName.Contains(DataColumn.HeaderText);
                }
            }
        }
        else
        {
            for (int Index = 0; Index < aGridView.Columns.Count; Index++)
            {
                DataColumn = aGridView.Columns[Index] as System.Web.UI.WebControls.BoundField;
                if (DataColumn != null)
                {
                    DataColumn.Visible = false;
                }
            }
        }
    }

Get ColumnIndex By DataColumn and HeaderText in Gridview

static public int GetColumnIndexByDBName(GridView aGridView, String ColumnText)
    {
        System.Web.UI.WebControls.BoundField DataColumn;
        for (int Index = 0; Index < aGridView.Columns.Count; Index++)
        {
            DataColumn = aGridView.Columns[Index] as System.Web.UI.WebControls.BoundField;
            if (DataColumn != null)
            {
                if (DataColumn.DataField == ColumnText)
                    return Index;
            }
        }
        return -1;
    }
static public int GetColumnIndexByHeaderText(GridView aGridView, String ColumnText)
    {
        TableCell Cell;
        for (int Index = 0; Index < aGridView.HeaderRow.Cells.Count; Index++)
        {
            Cell = aGridView.HeaderRow.Cells[Index];
            if (Cell.Text.ToString() == ColumnText)
                return Index;
        }
        return -1;
    }

Send email from classic asp using CDO

<% 
 Dim myMail,HTML,msg
 dim dbn
 dbn="../yourdbpath/Database.mdb"
 ID = Request("ID")
 fromAddress = Request.Form("fromAddress")
 Set cn = Server.CreateObject("ADODB.Connection")
 cn.provider="microsoft.jet.oledb.4.0"
 cn.connectionstring=server.mappath(dbn)
 cn.open
 'cn.Open cstring
 q = "SELECT * FROM users WHERE userid LIKE '" & fromAddress & "'"
 Set rs = cn.Execute(q)
 if rs.EOF then
  Response.write "<font color=""brown"" >Sorry! You have entered wrong Email Address or Email address not in the list.  </font>"
 else
  password=rs("password")
  msg = "User password helper! " & chr(10) & chr(10)
  msg = msg & "Please Use below password to login to user area " & Title & chr(10)
  msg = msg & "EmailAddress: " & fromAddress & chr(10)
  msg = msg & "Password: " & password & chr(10)
  Set myMail = Server.CreateObject("CDO.Message") 
  Dim cdoConfig 
  Set cdoConfig = myMail.Configuration 
  With cdoConfig.Fields 
  .Item("http://schemas.microsoft.com/cdo/configuration/sendusing") = 2 
  .Item("http://schemas.microsoft.com/cdo/configuration/smtpserver") = "mail.server.com" 
  .Item("http://schemas.microsoft.com/cdo/configuration/smtpserverport") = 25 
  '*** Authentication ***' 
  .Item ("http://schemas.microsoft.com/cdo/configuration/smtpauthenticate") = 1 
  .Item ("http://schemas.microsoft.com/cdo/configuration/sendusername") = "username" '*** User ***' 
  .Item ("http://schemas.microsoft.com/cdo/configuration/sendpassword") = "password" '*** Password ***' 
  .Item ("http://schemas.microsoft.com/cdo/configuration/smtpconnectiontimeout") = 30 
  .Update 
  End With 
  myMail.Configuration = cdoConfig
  myMail.From = "from@site.com"
  myMail.To   = fromAddress
  myMail.Subject =   "User password !"
  myMail.HTMLBody = msg 
  myMail.Send 
  Set myMail = Nothing 
  Response.write "<font color=""brown"" >Your pasword has been sent to your Email Address.. Pls check after some time. In case any problem Please contact the administrator </font>"
 end if
%> 

Add or Remove apostrophe to cell in active excel sheet

Option Explicit
Sub DeathToApostrophe()
    Dim s As Range, temp As String
    If MsgBox("Are you sure you want to remove all leading apostrophes from the entire sheet?", _
    vbOKCancel + vbQuestion, "Remove Apostrophes") = vbCancel Then Exit Sub
    Application.ScreenUpdating = False
    For Each s In ActiveSheet.UsedRange
        If s.HasFormula = False Then
             'Gets text and rewrites to same cell without   the apostrophe.
            s.Value = s.Text
        End If
    Next s
    Application.ScreenUpdating = True
End Sub

Sub AddApostrophes()
    Dim cel As Range
    Dim strw As String
    
    strw = "You cannot undo this task."
    strw = strw & " You may want to save your work to a new file."
    strw = strw & " Press OK to proceed, Cancel to quit."
    If vbCancel = MsgBox(strw, vbOKCancel + vbCritical, "Task Cannot Be Undone") Then Exit Sub
    
    For Each cel In ActiveSheet.UsedRange
        cel.Value = "'" & cel.Value
    Next cel
End Sub

How to use

1. Copy above code.
2. In Excel press Alt + F11 to enter the VBE.
3. Right-click desired file on left.
4. Choose Insert -Module.
5. Paste code into the right pane.
6. Press Alt + Q to close the VBE.
7. Save workbook before any other changes. 

Test the code

1. Ensure Active sheet is the desired sheet.
2. Press Alt + F8.
3. Choose 'DeathToApostrophe'.
4. Press 'Run'.
5. Confirm with 'Ok' to run.