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Visual Basic .NET Tutorial

How to Change the Data Type of a Column Using T-SQL

There are some cases that you need to change the data type of a field in SQL Server by not using the Management Studio Tools. The reason is if your database is replicated. You cannot change it directly using the management studio tools so your best option is to use T-SQL. In my case I have a column name “TransDate” that has a datetime datatype. Now when I create a report and filter the record

How to Differentiate Two Cell Values in DataGridView Control

I read a lot of question about this on the forum and thought it’s time to share with you on how to differentiate two cell values in DataGridView control. By default we use the Value property of cells like: QtyOrdered = InvoiceDetails("Qty", e.RowIndex).Value Another is to use the FormattedValue like: QtyOrdered = InvoiceDetails("Qty ", e.RowIndex).FormattedValue But the two code above will not

Correct Way to Open a Windows Form in VB.NET

Few months ago I encounter a problem with my windows form bound using a DataSet. When I open the form the first time, it seems that everything is fine. But when I open it again the second time, the fields are become blank. This happens when you trigger the “PerformClick” of “BindingNavigator” under the Form Load event. This is not actually the common mistake that I encounter. But maybe, you

ComboBox Binding Problem - Does Not Leave Focus

After browsing several forum sites I found so many programmers having problem with ComboBox after they bind it to a DataSet. The problem actually is not cause by a bug or the like. The error is caused by design. Here’s the following question on the internet that I found that will explain this error further: http://thedailyreviewer.com/dotnet/view/data-bound-combobox-does-not-leave-focus-106127786

Add MDI Form and Main Menu

In our previous tutorial I discuss on “How to Create Master/Detail Windows Forms” on our Library System Project. Today we will add MDI Form and create a main menu to open the forms on our project. If you follow closely this tutorial you will have now several Windows Forms on your project. Please follow the steps below to Add MDI Form and Main Menu on your Library System project. Click Project >>

Stop SelectedIndexChanged from Firing on Form Load Event

If you are using SelectedIndexChanged in your ComboBox may be you encounter a problem with events being fired even if you did not click the ComboBox. This happens when you open and close your Windows Form. The workaround for this is to use RemoveHandler statement. Here’s an example: RemoveHandler CreditTermIDComboBox.SelectedIndexChanged, AddressOf CreditTermIDComboBox_SelectedIndexChanged And

How to Create Master/Detail Windows Forms

On my last tutorial I discuss on “How to Display Data in Windows Forms”. This time I will teach you on “How to Create Master/Detail Windows Forms”. Creating a master/detail form still requires the same method as displaying data in windows forms. Except that we use additional control called “DataGridView”. This control will display the related record known as child form. In our database example the

How to Change Connection String at Run Time

One of the challenging parts in VB.NET is to change the connection string of your database location when you run your application. This tutorial will help you solve this problem. This will apply only to SQL Server but it can be also modified easily to work with MS Access and other DBMS. In my case I initialize this on the Form Load event on my Login form. Private Sub frmLogin_Load(ByVal sender As

How to Display Data in Windows Forms

In order to display data in windows forms all you need to do is drag Items from the Data Sources. For more information, see How to Add New Data Source. Before you drag the Items (i.e. table name) make sure that you select the display type and type of control that you’d like to appear in the Windows Forms. To do this expand the Item name and the arrow down to select the display type and type of

How to Debug Visual Studio .NET Project in 64 Bit OS

This tutorial will explain on: How to Debug Visual Basic .NET and Visual C# project in 64 bit Operating System. If you are running 32 Bit operating system before and were intrigued to install 64 bit OS to improved performance of your computer, then maybe you are having problems debugging your Visual Studio .NET source code. I am once having this issue which stops me from debugging all of my VB.NET