Below is an example of the automatically generated form Load Event and the manually-created Update button event handler for saving the data: Private Sub fm Main_Load(By Val sender As System. The Row Validating event and Error Provider may not be able to detect all errors.
For example, if a user types in alpha characters (like "abc") into a numeric field, a data conversion error occurs before Row Validation.
' Private Sub Data Grid View1_Row Validating(By Val sender As Object, By Val e As _ System. Row Validating ' Assume that text input is complete when you attempt to navigate ' away from the row Data Grid View1. In this case we're just checking to ' see if the Unit Price is a positive number If Data Grid View1. Luckily, the Data Grid View Combo Box Column control was designed to help solve this problem.
You can use a Data Grid View Combo Box Column to act a as "look up table" to show a user friendly version of the field, rather than just a numeric equivalent.
In this case we need a "global" error checker to detect data conversion errors.
' ' Check to see if the user input meets all of the business rules before ' we move on to another row. Data Grid View Cell Cancel Event Args) Handles _ Data Grid View1. Value The error checking discussed in the previous section may not detect "data integrity errors" (those errors where the input violates a database foreign key, unique, or primary key constraint).
Dim index As Integer ' find the location of the column index = Data Grid View1. Name = "Category" ' the column name (and heading) dgvc.
From inside the Form Designer, you should see a very small triangle at the upper right-hand corner of the Data Grid View control. For example, if the Units On Hand column can never be a negative number,you could write a validating rule that looks to see if the value is negative prior to committing the changes to that row.
Click on this triangle to select the data source that was created for you when you ran the Data Source Conversion Wizard. You can use the Error Provider class to display the problems detected during validation.
It has the initial "look and feel" of an Excel spreadsheet.
You can bind a Data Table to the control so the user can easily add/delete/modify data in a database. Products) End Sub By default, the automatically generated columns may need some tweaking.
At the conclusion of this wizard, you'll have a strongly-typed dataset, a Table Adapter, and Data Table added to your project. Products) End Sub ' ' Save the changes you've made via the Data Grid View back to the ' underlying database ' Private Sub bn Update_Click(By Val sender As System. Let's look at how you could perform some simple tweaks in a column that contains a Money field. Format = "$#.00" ' apply the style to the column Data Grid View1. Default Cell Style = style The major technique for detected errors in a Data Grid View is by the Row Validating event.