Posts Tagged ‘C#’

Class not registered

Posted: June 27, 2010 in .Net
Tags: , ,

Recently when I tried to build and run an existing .Net application code I got the following error which generated from a component named “axShockwaveFlash1” which is an object used to embed flash content on to the application.

System.Runtime.InteropServices.COMException was unhandled
  Message=Class not registered (Exception from HRESULT: 0x80040154 (REGDB_E_CLASSNOTREG))
  Source=System.Windows.Forms
  ErrorCode=-2147221164
  StackTrace:
       at System.Windows.Forms.UnsafeNativeMethods.CoCreateInstance(Guid& clsid, Object punkOuter, Int32 context, Guid& iid)
       at System.Windows.Forms.AxHost.CreateWithoutLicense(Guid clsid)
       at System.Windows.Forms.AxHost.CreateWithLicense(String license, Guid clsid)
       at System.Windows.Forms.AxHost.CreateInstanceCore(Guid clsid)
       at System.Windows.Forms.AxHost.CreateInstance()
       at System.Windows.Forms.AxHost.GetOcxCreate()
       at System.Windows.Forms.AxHost.TransitionUpTo(Int32 state)
       at System.Windows.Forms.AxHost.CreateHandle()
       at System.Windows.Forms.Control.CreateControl(Boolean fIgnoreVisible)
       at System.Windows.Forms.Control.CreateControl(Boolean fIgnoreVisible)
       at System.Windows.Forms.AxHost.EndInit()
       at Tour_Management_System.Loading_Form.InitializeComponent() in D:\Projects\Acc\TMS_20100205_Desktop\Tour_Management_System 2010-01-19\Tour_Management_System\Form1.Designer.cs:line 99
       at Tour_Management_System.Loading_Form..ctor() in D:\Projects\Acc\TMS_20100205_Desktop\Tour_Management_System 2010-01-19\Tour_Management_System\Form1.cs:line 30
       at Tour_Management_System.Program.Main() in D:\Projects\Acc\TMS_20100205_Desktop\Tour_Management_System 2010-01-19\Tour_Management_System\Program.cs:line 18
       at System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args)
       at System.Runtime.Hosting.ApplicationActivator.CreateInstance(ActivationContext activationContext, String[] activationCustomData)
       at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssemblyDebugInZone()
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart()
  InnerException:

After some investigation I found that the reason for this was Flash Player’s incompatibility with 64 bit. Since my machine is running Windows 64 bit version it generates an error while trying to start Flash player. Good thing is Adobe is planning to release a Flash player which supports 64 bit soon.

For people who cannot wait until that (like me) can fix the problem in the following manner by running the application as an x86 application by changing the target platform in project properties.

Step 1 – Right click on your project and click on the properties.

Step 2 – Click on the Build tab and select x86 as the Platform target:.

Step 3 – Rebuild the application and run it, you will not get the error.

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Even though I posted similar 2 articles in 2008, the code of that article was having few errors. So thought to put more complete post on this.

The code will read an Excel file using an OleDbConnection and will write the same data back to another Excel file. This will explain how to read and write to Excel files. One thing to remember when running this code is to make sure the source Excel file is open. Otherwise you will get an error similar to “External table is not in the expected format.”

Also note that there are few connection string parameters you can use while opening Excel files.

HDR = Yes – Use when first row contains column headers.

HDR = No  – Use when first row contains data.

Excel xx.x – Use the following Table as a guide.

Parameter Value

Excel Version

Excel 12.0 Excel 2007 (Released in 2007)
Excel 11.0 Excel 2003 (Released in 2003)
Excel 10.0 Excel XP (Released in 2001)
Excel 9.0 Excel 2000 (Released in 1999)
Excel 8.0 Excel 97 (Released in 1997)

IMEX=1 – Use this when you want to treat all your data in the file as text.

For example – >

Extended Properties="Excel 12.0 Xml;HDR=YES;IMEX=1";

To make the code to work properly you need to refer the Microsoft.Office.Interop.Excel assembly by adding a reference to your project.

  1. using System;
  2. using System.Data;
  3. using System.Windows.Forms;
  4. using System.Data.OleDb;
  5. using Microsoft.Office.Interop.Excel;
  6. namespace TestApp
  7. {
  8.     public partial class Form1 : Form
  9.     {
  10.         public Form1()
  11.         {
  12.             InitializeComponent();
  13.         }
  14.         private void button1_Click(object sender, EventArgs e)
  15.         {
  16.             openFileDialog1.ShowDialog();
  17.             // Create an OLEDBConnection to connect to the Excel file.
  18.             // I’m getting the required file by using a file dialog.
  19.             // The @ symbol makes the string to contain any special characters inside the string without breaking the string.
  20.             OleDbConnection dbConnection = new OleDbConnection(@"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + openFileDialog1.FileName.ToString() + @";Extended Properties=""Excel 8.0;HDR=Yes;""");
  21.             // Open the connection.
  22.             dbConnection.Open();
  23.             // Create a command object to work on the data.
  24.             // Note that I have given the sheet name as [Sheet1$] to retrieve data from that named sheet in the particular Excel file.
  25.             OleDbCommand dbCommand = new OleDbCommand("SELECT * FROM [Sheet1$]", dbConnection);
  26.             // Creating a data reader to read data.
  27.             OleDbDataReader dbReader = dbCommand.ExecuteReader();
  28.             // If needed you can get the position of any column (e.g. Age), this will only work if you use HDR=Yes.
  29.             int SearchingItem = dbReader.GetOrdinal("Age");
  30.             // Create the Excel Application object.
  31.             ApplicationClass ExcelApp = new ApplicationClass();
  32.             // Set the visibility of the application.
  33.             ExcelApp.Visible = true;
  34.             // Create a new Excel Workbook.
  35.             Workbook ExcelWorkbook = ExcelApp.Workbooks.Add(Type.Missing);
  36.             // Create a new Excel Sheet.
  37.             Worksheet ExcelSheet = (Worksheet)ExcelWorkbook.Sheets.Add(ExcelWorkbook.Sheets.get_Item(1), Type.Missing, 1, XlSheetType.xlWorksheet);
  38.             // Will keep the current row index. This should start from 1 since the first row is 1.
  39.             int CurrentRowIndex = 1;
  40.             try
  41.             {
  42.                 // Read through the data.
  43.                 while (dbReader.Read())
  44.                 {
  45.                     // Traverse through all the data columns.
  46.                     for (int i = 0; i < dbReader.VisibleFieldCount; i++)
  47.                     {
  48.                         ExcelSheet.Cells[CurrentRowIndex, i + 1] = dbReader.GetValue(i);
  49.                     }
  50.                     CurrentRowIndex++;
  51.                 }
  52.                 // Save the Excel sheet.
  53.                 // The @ symbol makes the string to contain any special characters inside the string without breaking the string.
  54.                 ExcelApp.Save(@"C:\Projects\Ex.xls");
  55.             }
  56.             catch (Exception ex)
  57.             {
  58.                 MessageBox.Show(ex.ToString());
  59.             }
  60.         }
  61.     }
  62. }

Creating an Excel Sheet using .Net

Posted: October 5, 2008 in .Net
Tags: , , ,
In this entry I will show how you can create a Microsoft Excel file using .Net.
// Create the Excel Application object.
ApplicationClass ExcelApp = new ApplicationClass();
// Set the visibility of the application.
ExcelApp.Visible = true;
// Create a new Excel Workbook.
Workbook ExcelWorkbook = ExcelApp.Workbooks.Add(Type.Missing);
// Create a new Excel Sheet.
Worksheet ExcelSheet = (Worksheet)ExcelWorkbook.Sheets.Add(ExcelWorkbook.Sheets.get_Item(1), Type.Missing, 1, XlSheetType.xlWorksheet);
try
{
   // Loop for 10 rows.
   for (int rwCount = 1; rwCount <= 10; rwCount++)
   {
      // Loop for 3 columns.
      for (int clmCount = 1; clmCount <= 3; clmCount++)
      {
         ExcelSheet.Cells[rwCount, clmCount] = "This is Row – " + rwCount + " Column – " + clmCount;
      }
   }
// Save the Excel sheet.
// The @ symbol makes the string to contain any special characters inside the string without breaking the string.
ExcelApp.Save(@"C:\Projects\Ex.xls");
}

Even though this is not new I do forget this always, so thought of putting an entry on how we can put a double quote inside of a string.
 
VB.NET
Dim str As String = "Example String " & """" & "This is the String with double quotes." & """"
MessageBox.Show(str)
In VB.Net you can indicate that there is a double quote in a string by using 4 double quotes ("""").
 
C#.NET
string str = "Example String " + "\"" + "This is the String with double quotes." + "\"";
MessageBox.Show(str);

As you will notice in C# the double quote can be represented as double quote, back slash and again using two double quotes ("\"").

The above string will be displayed as follows.

image