In Visual Studio Winforms applications you can set a column to hidden, and still use it to retrieve data from. If you set a column to inviisble in an ASP.NET application, the column is *not* available to get data from. If you set a column to invisible ad design time, the column is never bound […]
Author: bobnoordam
Hiding a control’s commandfield button at runtime
Hiding a command button at runtime can be archieved by casting the commandfield in the DataBound event, and accessing the buttons from there. The sample below shows the hiding of a button based on a security role. protected void DetailsViewDocuments_DataBound(object sender, EventArgs e) { // Check role string currentuser = Common.GetRequestUser(); // some user retrieval […]
Custom DataContext and Query with a Gridview bound to a LinqDataSource
Using an editable grid with a LinqDatasource with a custom connection string and query Binding to a custom datasource Create a custom datacontext object connected to the database to be used; private string _database; private SomeDataContext _dc; protected void Page_Load(object sender, EventArgs e) { _database = Common.GetRequestConnectionString(); _dc = new SomeDataContext(_database); } Catch the contextcreating […]
Setting the column width on a gridview column from code
To set the widht of a column on a GridView in ASP.NET you can hook into the RowDataBound event. This code detects the header line (datacontrolrowtype.header) and then hooks in to set the width of the columns. Instead of percentages you can use any Unit.* measure you like (pixels, mm) VB.NET Example Private Sub GridView1_RowDataBound(ByVal […]
Store and restore the currently selected cell on a datagridview
The standard .NET datagridview has several properties for active selections, but storing and restoring the current location of the user in the grid can be surprisingly un-intuitive. While you can use the SelectedRows propertie to query active selections, re-activating these selections in the rows[] collection, this will not restore focus to the row that was […]
Validation of a detailsview field against a numeric value
Validation of a field inside a detailsview does not need to be done with the Updating or Editing events, but can be accomplished by a simple validation control in the markup language. Convert the field in the detailsview to a template field, and use a standard validation control. <asp:CompareValidator ID=”CompareValidator2″ runat=”server” ErrorMessage=”Numeric input required” Operator=”DataTypeCheck” […]
ENTER key behaviour in ASP.NET
The behaviour of the ENTER key in an ASP.NET application can vary greatly between browsers and versions. Worse: It can change depending on the content of your page. Depending on this browser and version, you may also observe the form getting submitted, but the event handler code not executed… Especialy when using a pagemaster you […]
Validating DetailsView field values during Insert and Update
If you want to perform validation on the fields of a DetailsView at run time you can hook into the ItemInserting and ItemUpdating events as shown below. By Setting e.Cancel to true, it is possible to abort the insert/update action, and thus force the user to return to the form. /// <summary> /// Check if […]
Determine response time from an ip ping
‘ — ping the ip adress in the string s_ipaddr, and get ‘ the response time in the int32 n_response ‘ imports system.net.networkinformation Dim ping As New System.Net.NetworkInformation.Ping Dim reply As System.Net.NetworkInformation.PingReply reply = ping.Send(s_ipaddr) If reply.Status = IPStatus.Success Then ‘ — handle reachable here MsgBox(“ping time ” & reply.RoundtripTime) Else ‘ — handle non […]
Running a console command and capturing the output
This code sample demonstrates how to execute a console command and capture the output. The VB versions takes the “short route” using the shell command, while the C# version takes the approach of starting a process object, which gives you greater control over the proccess and enables you to pipe the outpout directly into the […]