Project | in VB.NET

Draw QR-Code in VB.NET Project |

Then back in the HTML-building code, I add fake URLs and SingleItemLink objects in tandem. Here s some of the code used to add in author links, given a data reader with author name fields. (The entryID value supplies the x in library://x.)

Do While dbInfo.Read ' ----- Add in this one author name. holdText = FormatAuthorName(dbInfo) entryID += 1 detailBody.AppendLine("<p><a href=""library://" & _ entryID & """>" & HTMLEncode(holdText & " [" & _ CStr(dbInfo!AuthorTypeName) & "]") & "</a></p>") ' ----- Add in an author link. newLink = New SingleItemLink newLink.LinkType = General.LookupMethods.ByAuthorID newLink.LinkID = CInt(dbInfo!ID) ItemLinkSet.Add(entryID, newLink) Loop

When the user clicks on a link in the embedded web browser, it triggers the Navigating event handler.

Private Sub SingleItemDetail_Navigating( _ ByVal sender As Object, ByVal e As System.Windows. _ Forms.WebBrowserNavigatingEventArgs) _ Handles SingleItemDetail.Navigating ' ----- Follow the clicked link. If (e.Url.Scheme = "library") Then _ FollowItemLink(CInt(e.Url.Host( ))) End Sub

The e.Url.Scheme property returns the portion of the URL before the :// characters, while e.Url.Host returns the first slash-delimited component just after these characters. That s where we stored the index into the ItemLinkSet dictionary. The FollowItemLink method extracts the lookup details from ItemLinkSet, and calls our trusty PerformLookup method, resulting in a new search that gets stored in the search history.

Private Sub FollowItemLink(ByVal entryID As Integer) ' ----- Given a character position in the single item ' text panel, follow the link indicated by that item. Dim scanLink As SingleItemLink ' ----- Access the link. scanLink = ItemLinkSet.Item(entryID) If (scanLink Is Nothing) Then Return ' ----- Perform a lookup as requested. If (PerformLookup(scanLink.LinkType, _ CStr(scanLink.LinkID), False) = False) _ Then Return ' ----- Store the history. AddLookupHistory(scanLink.LinkType, CStr(scanLink.LinkID)) End Sub

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The ItemLookup form is ready to use. We just need to call it from the search fields on the main form. The PanelLibraryItem panel in MainForm.vb includes several ComboBox selection controls, but there is no code to fill them in. Let s add that code now. Access the source code for MainForm.vb, and locate the MainForm_Load event. There s already some code there that adjusts the form elements. Append the new listfilling code to the end of this routine.

Here s the portion of that new code that fills in the list of search methods:

' ----- Load in the list of search types. SearchType.Items.Add(New ListItemData( _ "Lookup By Title", LookupMethods.ByTitle)) SearchType.SelectedIndex = 0 SearchType.Items.Add(New ListItemData( _ "Lookup By Author", LookupMethods.ByAuthor)) SearchType.Items.Add(New ListItemData( _ "Lookup By Subject", LookupMethods.BySubject)) SearchType.Items.Add(New ListItemData( _ "Lookup By Keyword (Match Any)", _ LookupMethods.ByKeywordAny)) SearchType.Items.Add(New ListItemData( _ "Lookup By Keyword (Match All)", _ LookupMethods.ByKeywordAll)) SearchType.Items.Add(New ListItemData( _ "Lookup By Publisher", LookupMethods.ByPublisher)) SearchType.Items.Add(New ListItemData( _ "Lookup By Series Name", LookupMethods.BySeries)) SearchType.Items.Add(New ListItemData( _ "Lookup By Barcode", LookupMethods.ByBarcode))

The Clear button on the search panel resets all of the search fields and prepares them for a new search. Add a new ActSearchClear_Click event handler either by using the method selection fields just above the code editor window, or by double-clicking on the Clear button on the form itself. Then add the following code to the handler.

' ----- Clear the current search criteria. SearchType.SelectedIndex = SearchType.Items.IndexOf( _ CInt(LookupMethods.ByTitle)) SearchText.Text = "" SearchMediaType.SelectedIndex = _

SearchMediaType.Items.IndexOf(-1) SearchLocation.SelectedIndex = _ SearchLocation.Items.IndexOf(-1)

Since the Library application will probably be used by many different patrons throughout the day, we should assume that a different person is using the program each time the form returns to the search panel. Let s simulate a click on the Clear button whenever the user views the search panel. Locate the existing TaskLibraryItem method, and add the following code to the end of the routine, just before the SearchText.Focus( ) statement.