Following is the sample code to write to the windows event log and display the contents of user selected windows event log on ASP.NET page.

Write to the windows event log:

 <%@ Import Namespace=”System.Data” %>
 <%@ Import Namespace=”System.Data.SQL” %>
 <%@ Import Namespace=”System.Diagnostics” %>

 <script language=”c#” runat=”server”>
 Private Sub Page_Load(source As [Object], e As EventArgs)
    ' Perform some type of illegal operation
    Try
        Dim objConn As SQLConnection
        objConn = New SQLConnection("server=localhost;uid=foo;pwd=bar;database=pubs")
        ' ...
        objConn.Open()
    Catch eError As Exception
        RecordError(eError, EventLogEntryType.[Error])
    End Try
End Sub

Private Sub RecordError(ByVal eError As Exception, ByVal enumType As EventLogEntryType)
    Const strSource As [String] = "ASP.NET", strLogName As [String] = "System"

    ' Add the strMessage entry to the ASPX event log
    Dim objLog As New EventLog(strLogName)
    objLog.Source = strSource
    objLog.WriteEntry(eError.Message, enumType)
End Sub
 </script>

Read the content of the windows event log:

 <%@ Import Namespace=”System.Diagnostics” %>
 <%@ Import Namespace=”System.Drawing” %>

 <script language=”VB” runat=”server”>
Sub Page_Load(ByVal source As Object, ByVal e As EventArgs)
    If Not Page.IsPostBack Then
        DisplayEventLog("System")
    End If
End Sub

Sub btnSubmit_OnClick(ByVal source As Object, ByVal e As EventArgs)
    DisplayEventLog(lstLog.SelectedItem.Value)
End Sub

Sub btnClear_OnClick(ByVal source As Object, ByVal e As EventArgs)
    'Clear all of the event log entries
    Dim objEventLog As New EventLog(lstLog.SelectedItem.Value)
    objEventLog.Clear()
End Sub

Sub DisplayEventLog(ByVal strLogName As String)
    Dim objRow As New TableRow
    Dim objCell As New TableCell

    objCell.BackColor = Color.Bisque
    objCell.HorizontalAlign = HorizontalAlign.Center
    objCell.Text = "Type"
    objRow.Cells.Add(objCell)

    objCell = New TableCell
    objCell.BackColor = Color.Bisque
    objCell.HorizontalAlign = HorizontalAlign.Center
    objCell.Text = "Date"

    objCell = New TableCell
    objCell.BackColor = Color.Bisque
    objCell.HorizontalAlign = HorizontalAlign.Center
    objCell.Text = "Time"
    objRow.Cells.Add(objCell)

    objCell = New TableCell
    objCell.BackColor = Color.Bisque
    objCell.HorizontalAlign = HorizontalAlign.Center
    objCell.Text = "Source"
    objRow.Cells.Add(objCell)

    objCell = New TableCell
    objCell.BackColor = Color.Bisque
    objCell.HorizontalAlign = HorizontalAlign.Center
    objCell.Text = "User"
    objRow.Cells.Add(objCell)

    objCell = New TableCell
    objCell.BackColor = Color.Bisque
    objCell.HorizontalAlign = HorizontalAlign.Center
    objCell.Text = "Computer"
    objRow.Cells.Add(objCell)

    tblLog.Rows.Add(objRow)

    Dim objEventLog As EventLog = New EventLog(strLogName)
    Dim objEntry As EventLogEntry

    For Each objEntry In objEventLog.Entries
        objRow = New TableRow
        objCell = New TableCell

        'Determine the type of error
        If objEntry.EntryType = EventLogEntryType.Error Then
            objCell.BackColor = Color.Red
            objCell.ForeColor = Color.White
            objCell.Text = "Error"
        ElseIf objEntry.EntryType = EventLogEntryType.Information Then
            objCell.Text = "Information"
        ElseIf objEntry.EntryType = EventLogEntryType.Warning Then
            objCell.BackColor = Color.Yellow
            objCell.Text = "Warning"

        ElseIf objEntry.EntryType = EventLogEntryType.SuccessAudit Then
            objCell.Text = "Success Audit"
        ElseIf objEntry.EntryType = EventLogEntryType.FailureAudit Then
            objCell.ForeColor = Color.Red
            objCell.Text = "Failure Audit"
        End If
        objCell.HorizontalAlign = HorizontalAlign.Center
        objRow.Cells.Add(objCell)

        objCell = New TableCell
        objCell.Text = objEntry.TimeGenerated.ToShortDateString()
        objRow.Cells.Add(objCell)

        objCell = New TableCell
        objCell.Text = objEntry.TimeGenerated.ToLongTimeString()
        objRow.Cells.Add(objCell)

        objCell = New TableCell
        objCell.Text = objEntry.Source
        objRow.Cells.Add(objCell)

        objCell = New TableCell
        If objEntry.UserName <> Nothing Then
            objCell.Text = objEntry.UserName
        Else
            objCell.Text = "N/A"
        End If
        objRow.Cells.Add(objCell)

        objCell = New TableCell
        objCell.Text = objEntry.MachineName
        objRow.Cells.Add(objCell)

        tblLog.Rows.Add(objRow)
    Next
End Sub
 </script>

 <html>
 <body>
 <form runat=”server”>
     <h1>Event Log Viewer</h1>
     <asplistbox runat=”server” id=”lstLog” Rows=”1”>
         <asplistitem>Application</asplistitem>
         <asplistitem>Security</asplistitem>
         <asplistitem Selected=”True”>System</asplistitem>
     </asplistbox>
     <aspbutton runat=”server” id=”btnSubmit” Text=”Display Event Log” OnClick=”btnSubmit_OnClick” />
     </hr>
     <asptable runat=”server” id=”tblLog” CellPadding=”5” CellSpacing=”0” GridLines=”Both” Font-Size=”10pt” Font-Name=”Verdana” />
     </hr>
     <aspbutton runat=”server” id=”btnClear” Text=”Clear Event Log” OnClick=”btnClear_OnClick” />
 </form>
 </body>
 </html>

User selects event log from provided dropdownlist and clicks display event log button; event log contents is displayed on ASP.NET page.