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

[Kenneth, GEOGRAF A/S]

Hmm, I see.
I am using an alternative API that has those properties, so I didn't 
verify that the properties were actually exposed.

Regards, Kenneth, GEOGRAF A/S



Maksim Sestic skrev:
> Hi Kenneth,
>
> It would be much easier if MgLayer had Filter property in first place :-)
> Alas, it doesn't (MGE 2008). It has FeatureSourceId and FeatureClassName
> properties, though, but not Filter property (and I have no clue why's that,
> probably somebody forgot to expose it).
>
> So I guess I still have to drill down the layer's XML definition to change
> the element value. But then, how do I change layer definition of runtime map
> and get it refreshed in Ajax viewer?
>
> Regards,
> Maksim Sestic
>
>
> Kenneth, GEOGRAF A/S wrote:
>   
>> 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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>>
>>
>>     
>
>   
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