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XML Books
by Paul Chu
Here is codet to fully edit a XML file
filename=/students/paulchu/xmlbookswithadd.aspx
<%@ Import Namespace="System.IO" %>
<%@ Import Namespace="System.Data" %>
<HTML>
<%'@ Page debug=true trace=true %>
<script language="VB" runat="server">
' ASP.NET concepts:
' datagrid , datatable, datarow
' ReadXML, WriteXML
' datagrid events: edit update delete
' system.io.File.exists Fileinfo, Streamwriter
'
' 02/14/02 -Enhancements to original version by Paul Chu
' 1. add code to support sorting
' 2. add code to support actual Updating and Deleting of XML data
' 3. add code to use javascript to confirm delete
' 4. Add new table to add author - add code to add a new row
' 5. Modify update and delete eventhandlers to update XML file using dataset
' 6. Hide Delete Column and Add Author panel when in edit mode
' 7. When all books have been deleted, add code to "make" a datatable
' Missing Features:
' No Validation in add / edit
'
' 8. Support creating a new XML file from scratch: create a new file if it is not found
'
' Ok, before you get all excited, the job is not done
'
' Field validation logic needs to be added
' the Delete Book method relies on not having asp validator objects
'
' You also need to verify that the ISBN is not already in the
' the dataset ( or will it detect it because we have isbn defined as a key )
'
dim gXmlfile as string = "/experiments/data/paulchubooks.xml" ' <============ your file
dim gXmlPath as string
' =================================
Sub Page_Load(Src As Object, E As EventArgs)
gxmlpath = server.mappath( gXmlfile ) 'file is in same folder as page
If Not (IsPostBack)
DataLoad("isbn") '-- sort by ISBN
End If
End Sub
' =================================
Sub DataLoad(parmsort as string)
Dim ds As DataSet = new dataset()
Dim FS As FileStream
if file.exists( gXmlpath) then
FS = New FileStream( gXmlpath , FileMode.Open)
ds.ReadXml(FS)
FS.close()
else
createnewfile( gxmlpath) 'create a new XML file
end if
' 02/14/02 pchu handle an empty file ---------------------------
if ds.tables.count = 0 then
ds.tables.add( MakeBooksTable() ) 'create a DataTable in the dataset
end if
' 02/14/02 pchu ---------------------------
' Add code to sort the dataview if parmsort is present
dim dv as dataview
dv = new DataView(ds.Tables(0))
if parmsort.length > 0 then
dv.sort = parmsort
end if
MyDataGrid.DataSource = dv
'old MyDataGrid.DataSource = new DataView(ds.Tables(0))
' 02/14/02 pchu ---------------------------
MyDataGrid.DataBind()
END SUB
' =================================
sub createnewfile(byval filepath as string )
'-- create a new file if necessary
dim f as fileinfo = new fileinfo( filepath )
dim writer as streamwriter = f.createtext()
writer.writeline ("<books></books>") 'create a root element
writer.close()
trace.warn ("new file created", filepath )
end sub
' =================================
Sub DataSort(Src As Object, E As DataGridSortCommandEventArgs)
' Bug if we sort, then Edit Item Becomes Wrong
IF MyDataGrid.EditItemIndex=-1 THEN
DataLoad(e.sortexpression)
ELSE
response.write ("Can't sort until editing is done!")
END IF
End Sub
' =================================
Sub DataDelete(Sender As Object, E As DataGridCommandEventArgs)
DIM deletekey as string
IF MyDataGrid.EditItemIndex = -1 THEN
deletekey=MyDataGrid.DataKeys(CInt(E.Item.ItemIndex))
response.write ("Delete completed for key = " & deletekey)
ELSE
response.write ("Can't delete until editing is done!")
END IF
Dim currentRow As Integer = e.Item.DataSetIndex
' reload the XML file into a dataset
Dim ds As New DataSet()
ds.ReadXml( gXmlPath )
' get a reference to this row of data
Dim row As DataRow = ds.Tables(0).Rows( currentrow )
row.delete() '-- kill this row in the dataset
' save the updated dataset to the XML file
ds.WriteXml( gXmlPath )
mydatagrid.EditItemIndex = -1 'exit delete mode
dataload("") ' redisplay and rebind datagrid
END SUB
' =================================
Sub DataEdit(Sender As Object, E As DataGridCommandEventArgs)
DIM editkey as string
MyDataGrid.EditItemIndex = Cint(E.Item.ItemIndex)
editkey=MyDataGrid.DataKeys(CInt(E.Item.ItemIndex))
trace.warn ("page.aspx", "To Be Edited" & editkey)
SetEditMode( "on" )
DataLoad("")
End Sub
' =================================
Sub DataCancel(Sender As Object, E As DataGridCommandEventArgs)
MyDataGrid.EditItemIndex = -1
trace.warn ("page.aspx", "edit was cancelled")
SetEditMode( "off" )
DataLoad("")
End Sub
' =================================
Public Sub DataUpdate(ByVal source As Object, ByVal e _
As System.Web.UI.WebControls.DataGridCommandEventArgs)
Dim cols As String() = {"isbn", "author", "title", "category", "comments"}
Dim numCols As Integer = e.Item.Cells.Count
Dim currentRow As Integer = e.Item.DataSetIndex
' reload the XML file into a dataset
Dim ds As New DataSet()
ds.ReadXml( gXmlPath )
' get a reference to this row of data
Dim row As DataRow = ds.Tables(0).Rows(e.Item.DataSetIndex)
' get the values and update the datarow
Dim I, J As Integer
j = -1
Trace.Warn("aspx.page", "numcols = " & CStr(numCols))
For I = 2 To numCols - 1 'skip first and 2nd columns (Edit/Delete command column)
j += 1
Dim currentTextBox As TextBox
currentTextBox = CType(e.Item.Cells(I).Controls(0), TextBox )
row(cols(j)) = currentTextBox.Text
Trace.Warn(I.ToString(), CStr(cols(j)) & " = " & currentTextBox.Text)
Next
' save the updated data as the XML file
ds.WriteXml( gXmlPath )
SetEditMode( "off" )
mydatagrid.EditItemIndex = -1
dataload("")
End Sub
' =================================
sub SetEditMode ( state as string)
select case state
case "on"
MyDataGrid.columns(0).visible = False 'Hide Delete Column
panela.visible = False 'Hide Add Author
case else
MyDataGrid.columns(0).visible = True 'Show Delete Column
panela.visible = True 'Show Add Author
end select
end sub
' =================================
public sub dg_itemcreated ( sender as object, e as datagriditemeventargs )
select case e.item.itemtype
case listitemtype.item
dim mydeletebutton as tablecell
mydeletebutton = e.item.cells(0)
mydeletebutton.attributes.add("onclick", _
"return confirm('Are you sure you want to Delete ?');" )
case listitemtype.alternatingitem
dim mydeletebutton as tablecell
mydeletebutton = e.item.cells(0)
mydeletebutton.attributes.add("onclick", _
"return confirm('Are you sure you want to Delete ?');" )
end select
end sub
' =========================
Sub AddAuthor(ByVal sender As System.Object, ByVal e As System.EventArgs)
trace.warn ("AddAuthor", "Beg" )
'''response.write ("<HR>Work in Progress<HR>")
'----------
' reload the XML file into a dataset
Dim ds As New DataSet()
ds.ReadXml( gXmlPath )
' 02/14/02 pchu handle an empty file ---------------------------
if ds.tables.count = 0 then
ds.tables.add( MakeBooksTable() )
end if
' create a new datarow object
Dim row As DataRow = ds.tables(0).newrow()
dim sw1 as integer = 2
select case sw1
case 1
Dim cols As String() = {"isbn", "author", "title", "category", "comments"}
row( cols(0) ) = xisbn.text
row( cols(1) ) = xauthor.text
row( cols(2) ) = xtitle.text
row( cols(3) ) = xcategory.text
row( cols(4) ) = xcomments.text
case 2
row( "isbn" ) = xisbn.text
row( "author" ) = xauthor.text
row( "title" ) = xtitle.text
row( "category" ) = xcategory.text
row( "comments" ) = xcomments.text
end select
ds.tables(0).rows.add(row) 'add our datarow to the table in ds
' save the updated data as the XML file
ds.WriteXml( gXmlPath )
'---------
dataload("") ' re-display xml file
ClearForm()
' clear ADD author form
trace.warn ("AddAuthor", "End" )
End Sub
' =========================
Sub ClearForm()
xisbn.Text = ""
xauthor.Text = ""
xcategory.Text = ""
xtitle.Text = ""
xcomments.Text = ""
End Sub
' ===================================
Private Function MakeBooksTable() As DataTable
'' theColumn.DefaultValue = "Fname"
' Dim fNameColumn As DataColumn = New DataColumn()
'' idColumn.AutoIncrement = True
' Create a new DataTable titled 'Books.'
Dim theTable As DataTable = new DataTable("Books")
' Add three column objects to the table.
Dim theColumn1 As DataColumn = new DataColumn()
theColumn1.DataType = System.Type.GetType("System.String")
theColumn1.ColumnName = "isbn"
theTable.Columns.Add(theColumn1)
Dim theColumn2 As DataColumn = new DataColumn()
theColumn2.DataType = System.Type.GetType("System.String")
theColumn2.ColumnName = "author"
theTable.Columns.Add(theColumn2)
Dim theColumn3 As DataColumn = new DataColumn()
theColumn3.DataType = System.Type.GetType("System.String")
theColumn3.ColumnName = "title"
theTable.Columns.Add(theColumn3)
Dim theColumn4 As DataColumn = new DataColumn()
theColumn4.DataType = System.Type.GetType("System.String")
theColumn4.ColumnName = "category"
theTable.Columns.Add(theColumn4)
Dim theColumn5 As DataColumn = new DataColumn()
theColumn5.DataType = System.Type.GetType("System.String")
theColumn5.ColumnName = "comments"
theTable.Columns.Add(theColumn5)
' Create an array for DataColumn objects.
Dim keys(0) As DataColumn
keys(0) = theColumn1
theTable.PrimaryKey = keys
' Return the new DataTable.
MakeBooksTable = theTable
End Function
</script>
<!-- =================================================== -->
<body>
<h3><font face="Verdana">The Best Books Ever: Enhanced Version by Paul Chu</font>
<span runat="server" id="MySpan"></h3>
<h2>Updateable Datagrid and Add Form to update xml file: <% = gXmlFile %></h2>
<form runat="server">
<P>
<ASP:DataGrid id="MyDataGrid" runat="server"
AllowSorting="True"
OnSortCommand="DataSort"
OnDeleteCommand="DataDelete"
OnEditCommand="DataEdit"
OnCancelCommand="DataCancel"
OnUpdateCommand="DataUpdate"
DataKeyField="isbn"
Width="100%"
BackColor="White"
BorderColor="Black"
CellPadding=3
Font-Name="Verdana"
Font-Size="8pt"
Headerstyle-BackColor="lightblue"
Headerstyle-Font-Size="10pt"
Headerstyle-Font-Style="bold"
MaintainState="true"
Font-Names="Verdana"
onitemcreated="dg_itemcreated"
>
<HeaderStyle Font-Size="10pt" BackColor="LightBlue">
</HeaderStyle>
<Columns>
<asp:ButtonColumn Text="Delete Book" CommandName="Delete"></asp:ButtonColumn>
<asp:EditCommandColumn ButtonType="LinkButton" UpdateText="Update" CancelText="Cancel" EditText="Edit">
<ItemStyle Wrap="False">
</ItemStyle>
</asp:EditCommandColumn>
</Columns>
</ASP:DataGrid></P>
<asp:Panel ID=panela visible=True Runat=server>
<TABLE id=Table1 cellSpacing=1 cellPadding=1 width=300 border=1>
<TR>
<TD bgColor=lightblue colSpan=3>
<P align=center>Add New Author</P></TD></TR>
<TR>
<TD>ISBN:</TD>
<TD><asp:TextBox id=xisbn runat="server"></asp:TextBox></TD>
<TD></TD></TR>
<TR>
<TD>Author:</TD>
<TD><asp:TextBox id=xauthor runat="server"></asp:TextBox></TD>
<TD></TD></TR>
<TR>
<TD>Title:</TD>
<TD><asp:TextBox id=xtitle runat="server"></asp:TextBox></TD>
<TD></TD></TR>
<TR>
<TD>Category:</TD>
<TD><asp:TextBox id=xcategory runat="server"></asp:TextBox></TD>
<TD></TD></TR>
<TR>
<TD>Comments:</TD>
<TD><asp:TextBox id=xcomments runat="server" TextMode="MultiLine"></asp:TextBox></TD>
<TD></TD></TR>
<TR>
<TD colSpan=3>
<P align=center><asp:Button id=btnSubmit onclick=AddAuthor runat="server" Text="Add Author"></asp:Button></P></TD></TR></TABLE>
<P> </P>
</asp:Panel>
</form></SPAN>
</body>
</HTML>
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