Error : Validation of viewstate MAC failed. If this application is hosted by a Web Farm or cluster, ensure that <machinekey> configuration specifies the same validationKey and validation algorithm. AutoGenerate cannot be used in a cluster.Solution : Add this part to the web.config System.Web section:<pages enableEventValidation="false" viewStateEncryptionMode...
Tuesday, June 30, 2009
Thursday, June 25, 2009
Fail loading Web Application Project
Error : I do not quite remember the exact error, encounter it long time ago, and just now, a friend asked about it again. The error contain the words ..... System.Runtime.InteropServices.COMException...It is characterized by web application project not being loaded while opening a solution, while any other projects open well.Solution : Check whether...
Debug not working on VS 2003.Net
Problem : Debug is not working on Visual Studio.NET 2003. There are some problems with Visual Studio 2003. Yet, still using it in some projects. One common problem is that the debug is not attached to the process while run in debugging mode. Hence, the breakpoints set will not be hit. This is sometimes annoying, when errors occur, and we're looking...
Thursday, June 18, 2009
Can not add service reference / web reference
Error : The components required to enumerate web references are not installed on this computer. Please re-install Visual studio.This error pops up as a dialog box while trying to add service reference / web reference.Solution : Press window + Run, then type "devenv /resetskippkgs" (without quotes), then press Enter.This command clears all options ...
Error with web service
Error variations:- No connection could be made because the target machine actively refused it.- The request failed with HTTP status 404: Not FoundSolution : Check whether the URL for the web service is set properly.This problem appears to be a debugging problem when web service is used for desktop application. Yet, it appears to be a deploying problem...
Wednesday, June 17, 2009
Creating Simplified Duwamish from a scratch
This is a step by step on how to create an asp.net C# web application using simplified Duwamish framework. I call it simplified Duwamish framework, because it is not the real Duwamish. It is my own version. I like it better, after eliminating some parts of the Duwamish framework...
Tuesday, June 16, 2009
Logon failed on Crystal Report
Error : Logon failed. Details: ADO Error Code: 0x Source: Microsoft OLE DB Provider for SQL Server Description: Login failed for user 'UserXXX'. SQL State: 42000 Native Error: Error in File E:\TEMPSY~1\Tmp\temp_xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx {xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx}.rpt: Unable to connect: incorrect log on parameters.Solution :...
Saturday, June 13, 2009
Appending ArrayList to another ArrayList
A friend of mine asked about how to append an ArrayList to another ArrayList in C#. I found out that it's an easy task as long as the type of the ArrayList is the same. Just have to typecast it to ICollection.e.g.ArrayList a = new ArrayList();a.Add("Array 1");a.Add("Array 2");ArrayList b = new ArrayList();b.Add("Array 3");b.Add("Array 4");a.AddRan...
Tuesday, June 9, 2009
Open and close CD-ROM tray in VB
Create a module, and put this code in it:Declare Sub mciSendStringA Lib "winmm.dll" (ByVal lpstrCommand As String, ByVal lpstrReturnString As Any, ByVal uReturnLength As Long, ByVal hwndCallback As Long)To Open CD-ROM tray, use this method:Sub OpenCDTray() mciSendStringA "Set CDAudio Door Open", 0&, 0, 0End SubTo Close CD-ROM tray, use this...
Delete data by date
Sometimes, new Visual Basic developers may meet such problems as retrieving data by date. Just need to use # to make it righte.g.db.Execute "DELETE FROM table_name WHERE FieldDate < #" & Format(Date, "yyyy/mm/dd") & ...
Tuesday, June 2, 2009
Data on report won't change
Problem : If you're using crystal report to design a report and the data displayed on the report won't change.Solution : Go check the report. Open it, then make sure that on menu File -> Save Data With Report -> is NOT checked.This is actually a minor problem, but sometimes, people forget or don't notice ...
Invalid Handle in Crystal Report
Error : Invalid HandleAn error dialog box which says "Invalid Handle" shows while saving crystal report document.Solution : The solution may vary in this case. Sometimes, there isn't even any mistake with the report.1. Search for crw32.exe on the computer, in accordance with the version of Crystal Report being used, right-click the file -> properties...
