[mapguide-users] Changing existing dynamic layer's Filter on the fly

[Kenneth, GEOGRAF A/S]

When the MapDefinition is turned into a runtime Map, it copies 
properties from the layerdefinition.
This means that you will see no changes, even if you choose to modify 
the LayerDefinition.

You must modify the layer copy in the runtime map.
Fortunately, that is actually easier than what you are doing now:

MgMap map = new MgMap();
map.Open("map", srv);

map.Layers("layername").Filter = "Column = 5";
map.Save();

Regards, Kenneth, GEOGRAF A/S



Maksim Sestic skrev:
> I think I'm having problems with changing existing dynamic layer's Filter
> property (the one that filters data from FeatureSource) using .NET. Here's
> the approach that doesn't report any error, but when I refresh the map there
> are no changes to the layer - new filter doesn't get applied.
>
> Dim layer As MgLayer = ...getting a MgLayer object...
> Dim document As New XmlDocument
> document.PreserveWhitespace = True
> Dim byteReader As MgByteReader =
> resources.Service.GetResourceContent(layer.LayerDefinition)
> document.LoadXml(byteReader.ToString)
>
> Allright, it's all in XmlDocument now and then I do some parsing to change
> the Filter element. When I save the definition to XML file (just for
> testing) everything's OK, structure and data is preserved and Filter element
> is set to some new value.
>
> ' Saving XmlDocument to memory stream
> Dim stream As MemoryStream = New System.IO.MemoryStream()
> document.Save(stream)
>
> ' Converting stream to byte array 
> Dim byteArray() As Byte = stream.ToArray
>
> ' Converting byte array to String (BOM included, otherwise SetResource
> raises an error while parsing XML)
> Dim outerXml As String = System.Text.Encoding.UTF8.GetString(byteArray, 0,
> byteArray.Length - 1)
>
> ' Converting String to byte array with UTF-8 encoding 
> byteArray = System.Text.Encoding.UTF8.GetBytes(outerXml)
>
> ' Creating MgByteSource out of byte array, setting appropriate MimeType
> Dim byteSource As MgByteSource = New MgByteSource(byteArray,
> byteArray.Length)
> byteSource.SetMimeType(MgMimeType.Xml)
>
> ' Getting MgResourceIdentifier corresponding to current SessionId and
> existing Layer name
> Dim resourceId As New
> MgResourceIdentifier(String.Format("Session:{0}//{1}.LayerDefinition",
> sessionId, layerName))
>
> ' Setting a resource (without Header) using MgResourceIdentifier and byte
> source
> resources.Service.SetResource(resourceId, byteSource.GetReader, Nothing)
>
> ' I don't know if this is necessary, but still...
> layer.ForceRefresh()
>
>
> Now, when I call parent.parent.Refresh() on the client side nothing happens.
> What am I doing wrong here?
>
> Regards,
> Maksim Sestic
>
>
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