CODEWITHSUNDEEP
wpfdata-binding
Sergey
Sergey

Reputation: 301

Custom XML Data Provider (WPF)

I want to create my own XML data provider derived from DataSourceProvider (similar XmlDataProvider).

(i don't want use XmlDataProvider because i want return alternative data if XPath query is failed)

But i can't understand how to access XPath property which set via Binding.XPath.

For example, i have class:

public class MyXmlDataProvider : DataSourceProvider
{
    private string _xPath;
    public string XPath
    {
        // The following code i spied from XmlDataProvider implementation using .Net Reflector
        get
        {
            return this._xPath;
        }
        set    // WHY binding do not call this setter? ((
        {
            if (this._xPath != value)
            {
                this._xPath = value;
                if (!base.IsRefreshDeferred)
                {
                    base.Refresh();
                }
            }
        }
    }

    private string _result;
    protected override void BeginQuery()
    {
        // .... getting result using XPath

        base.OnQueryFinished(_result);
    }
}

XAML binding example (mydata - instance of MyXmlDataProvider class):

<TextBlock Text="{Binding Source={StaticResource mydata}, XPath=/main/version}" />

Question is: How can i get Binding.XPath value in MyXmlDataProvider class?

Upvotes: 1

Views: 1227

Answers (1)

Sergey
Sergey

Reputation: 301

I found source code of XmlDataProvider here:

http://reflector.webtropy.com/default.aspx/DotNET/DotNET/8@0/untmp/WIN_WINDOWS/lh_tools_devdiv_wpf/Windows/wcp/Framework/System/Windows/Data/XmlDataProvider@cs/4/XmlDataProvider@cs

But i solved my task by implementing a class with indexer (not a descendent of DataSourceProvider):

public string this[string xpath]
{
  // Here i do XPath-query and handle its result
  ...
}

XPath-query i set in the binding as follows:

<TextBlock Text="{Binding Source={StaticResource mydata}, Path=[/main/version]}" />

Upvotes: 2

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