This is the first time I'm working with List

Here is my code (Removed all the unwanted lines for simplification)

Class1

public class RInfo 
{
    public int RCode { get; set; }
    public int ACode { get; set; }
    public int DCode { get; set; }
    public string RNo { get; set; }
    //public DateTime EDate { get; set; }
    //public DateTime? VDate { get; set; }
}

Class 2

public class DInfo 
{
    public int DCode { get; set; }
    public string DName { get; set; }
    public bool DCExpires { get; set; }
}

Class that I will get after joining above two classes

public class RInfo_Details
{
    public int RCode { get; set; }
    public int ACode { get; set; }
    public int DCode { get; set; }
    public string DCName { get; set; }
    public string DName { get; set; }
    public string RNo { get; set; }
    //public DateTime EDate { get; set; }
    //public DateTime? VDate { get; set; }
}

Here is my class this is used to retrive data and for binding in XAML

public class AppData : INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;
    protected void RaisePropertyChanged(string propertyName) => PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));

    private AppData() { }

    private static AppData instance = null;

    public static AppData Instance
    {
        get
        {
            if (instance == null) instance = new AppData();
            return instance;
        }
    }

    AInfo _SelAInfo;
    public AInfo SelAInfo
    {
        get => _SelAInfo; set
        {
            _SelAInfo = value; RaisePropertyChanged(nameof(SelAInfo));
            RaisePropertyChanged(nameof(RInfo_List));
            RaisePropertyChanged(nameof(RInfoDetailedList));
        }
    }

    List<DInfo> _DInfo;
    public List<DInfo> DInfo { get => _DInfo; set { _DInfo = value; RaisePropertyChanged(nameof(DInfo)); } }

    List<RInfo> _RInfo;
    public List<RInfo> RInfo { get => _RInfo; set { _RInfo = value; RaisePropertyChanged(nameof(RInfo)); RaisePropertyChanged(nameof(RInfoDetailedList)); } }

    public IEnumerable<RInfo_Details> RInfoDetailedList
    {
        get
        {
            IEnumerable<RInfo_Details> newlist = (from r in RInfo
                                                  join d in DInfo
                                                  on r.DCode equals d.DCode
                                                  select new
                                                  {
                                                      r.RCode,
                                                      r.ACode,
                                                      r.DCode,
                                                      d.DName,
                                                      d.DCExpires,
                                                      r.RNo,
                                                  }).ToList() as IEnumerable<RInfo_Details>;

            return newlist as IEnumerable<RInfo_Details>;
        }
    }

    public void iniTestData()
    {
        this.DInfo = new List<DInfo>()
        {
            new DInfo{DCode=1, DCExpires=false, DName="PAN" },
            new DInfo{DCode=2, DCExpires=true, DName="FSSAI" },
            new DInfo{DCode=3, DCExpires=false, DName="AANDAHR" }
        };

        this.RInfo = new List<RInfo>()
        {
            new RInfo{RCode=1, ACode=1, DCode=1, RNo="PAN NO ACode 1" },
            new RInfo{RCode=2, ACode=2, DCode=1, RNo="PAN NO ACode 2" },
            new RInfo{RCode=3, ACode=5, DCode=3, RNo="AADHAR ACode 5" },
            new RInfo{RCode=4, ACode=4, DCode=1, RNo="PAN NO ACode 4" }
        };
    }
}

Here is code in XAML that is binding AppData.RInfoDetailedList

        <ListView ItemsSource="{Binding Source={x:Static local:AppData.Instance}, Path=RInfoDetailedList}">
        <ListView.ItemTemplate>
            <DataTemplate>
                <Grid>
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition/>
                        <ColumnDefinition/>
                        <ColumnDefinition/>
                    </Grid.ColumnDefinitions>
                    <Label Grid.Column="0" Content="{Binding RNo}"/>
                    <Label Grid.Column="1" Content="{Binding DName}"/>
                    <Label Grid.Column="2" Content="{Binding DCExpires }"/>
                </Grid>
            </DataTemplate>
        </ListView.ItemTemplate>
    </ListView>

Data from RInfo & DInfo Binds succesfully. but from RInfoDetailedList does not bind. What is that I'm missing

CodePudding user response：

This is because RInfoDetailedList is returning null due to the wrong cast!

You can create the RInfo_Details object in the select statement like this

public IEnumerable<RInfo_Details> RInfoDetailedList
{
    get
    {
        if (RInfo == null || DInfo == null) return null;   
        var newList = from r in RInfo
            join d in DInfo
                on r.DCode equals d.DCode
            select new RInfo_Details {
                RCode = r.RCode,
                ACode = r.ACode,
                DCode = r.DCode,
                DName = d.DName,
                RNo = r.RNo,
            };

        return newList;
    }
}