在 WPF DataGrid 中使用多个 XML 文档

Question

So for a project I am working on I have a slight problem I can't figure out how to best solve.

In principle the application will start by loading an XML file that I will always know the location and contents of and displaying this in a DataGrid for the user to view.

The user can then go onto other sections of the application to input data that they wish to be exported into an XML in the same format as the original, however the kicker is that these "edits" must never overwrite the original, I will need the new inputs or edits to be saved on a seperate XML file.

I can handle that section just fine, however I then want if possible to have the DataGrid show a combination of both of the XML Files (and potentially it needs to be able to check if the new file overlaps and decide which one to show).

I've been making the program in WPF, any thoughts would be great.

Thanks.

Answer 1

Data Grid - an element derived from ItemsControl. All such elements work with only one data source. The data source must be IEnumerable.

Your two XML files are two different data sources.

I see two solutions.

Create a UserConrol containing two DataGrid and synchronize the scroll of lines in them.

In ViewModel, from two source files, create one complex collection containing data from both files.

Answer 2

Serialisation and deserialisation is the simple csharp friendly way to work with xml.

You want xml on disk but your code will be far easier to work with if you bind ObservableCollection rather than some object source directly from xml.

If this is a new concept to you start reading here:

https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/concepts/serialization/

This would involve serialising a class which has a public property that's a List where t is the class corresponding to each node of your xml file.

Here is some generic serialisation and deserialisation code:

    public static void saveType<T>(T obj, string fileURL)
    {
        if (!fileURL.EndsWith(".xml"))
        {
            fileURL += ".xml";
        }
        using (FileStream writer = new FileStream(fileURL, FileMode.Create))  // FileMode.Create will over write an existing file
        {
            DataContractSerializer ser = new DataContractSerializer(typeof(T));
            ser.WriteObject(writer, obj);
        }
    }
    public static T readType<T>(string fileURL)
    {
        if (!fileURL.EndsWith(".xml"))
        {
            fileURL += ".xml";
        }
        var deserializedObj = Activator.CreateInstance(typeof(T));

        if (!File.Exists(fileURL))
        {
            MessageBox.Show($"No file found at {fileURL}");
            return (T)deserializedObj;
        }

        FileStream fs = new FileStream(fileURL, FileMode.Open);
        XmlDictionaryReader reader = XmlDictionaryReader.CreateTextReader(fs, new XmlDictionaryReaderQuotas());
        DataContractSerializer ser = new DataContractSerializer(typeof(T));
        deserializedObj = (T)ser.ReadObject(reader, true);
        reader.Close();
        fs.Close();
        return (T)deserializedObj;
    }

    public static void SaveArmy(string fileURL, Army army)
    {
        saveType<Army>(army, fileURL);
    }

    public static Army ReadArmy(string fileURL)
    {
        Army army = readType<Army>(fileURL);
        return army;
    }

All you need to do is have public properties, no attributes are necessary for that to work.

The properties can be themselves complex objects so you can have things like a list as a property of each.

You may also want a property in your class which you can use to tell you the origin of a record. Is this from original file or merged in from edited file, for example.

Use Linq to merge your lists of data.

for example:

var combinedList = listOriginal.Union(listNew).ToList();

I'm not clear what you do with the combined lists but that's how you'd get them into one.

If there is logic involved you could potentially manipulate that list further and translate into another list of viewmodels.

You can then bind that list to the itemssource of a listview or datagrid.

As I write this, it's clear to me that there is much you've not explained about your question. I strongly recommend you edit your post and clarify your requirements. Because your question is likely to be closed otherwise.

Answer 3

I decided to just give up and use 2 data grids instead.