WPF Datagrid + MVVM + Header Change by ViewModel

Raghunath Pentela

with autogeneratecolumns true.

I have two table entities in a Dbcontext Model. Table2 contains all configuration of column for e.g Header Fieldname, Header Description, Color, Font e.t.c

I am populating table1 in wpf datagrid through viewmodel. I want to replace the header names with the header description of table2 through MVVM

Table1:

(Default WPF Datagrid)

SrNo Col1 Col2

Table2:

FieldName Description

SrNo Serial No

Col1 Name

Col2 Age

My datagrid should be

Serial No Col1 Col2

My table1 and table2 are dynamic and autogenerate columns must be true.

10 Replies

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Mario Scheeren7y ago
Nope, bc your solution will never be dynamic and has to be hardcoded.
And having in mind you want AutoGenerateColumns not knowing what properties will come there is no better way I know. YXou will need to somehow generate an annonymous object with an unknown amount of properties which itself needed to be mapped / translated getting values from another object.

Maybe you add some kind of MappingAttribute or NamingAttribute yourself to those objects. Since you use EF I bet the models won't change all the time so generating som ExtensionMethod to map to another object might work as well.
Raghunath Pentela7y ago
modelBuilder.Entity().Map(m =>
{
m.Properties(t => new { t.PersonId });
m.Property(t => t.Name).HasColumnName("PersonName");
m.ToTable("People");
}).Map(m =>
{
m.Property(t => t.PersonId).HasColumnName("ProprietorId");
m.Properties(t => new { t.AddressLine, t.City, t.ZipCode });
m.ToTable("PersonDetails");
});

Can we do something like above
Mario Scheeren7y ago
Then do map to another type:
static DataTable MapMyTables(IEnumerable dataTable1, IEnumerable dataTable2)
{
    Funcobject>> genAccessor = prop =>
    {
        // Define the parameter that will be passed - will be the current object
        var parameter = Expression.Parameter(typeof(DataTable1), "input");

        // Define an expression to get the value from the property
        var propertyAccess = Expression.Property(parameter, prop.GetGetMethod());

        // Make sure the result of the get method is cast as an object
        var castAsObject = Expression.TypeAs(propertyAccess, typeof(object));

        // Create a lambda expression for the property access and compile it
        var lamda = Expression.Lambdaobject>>(castAsObject, parameter);
        return lamda.Compile();
    };

    var props = typeof(DataTable1)
        .GetProperties(BindingFlags.Instance | BindingFlags.Public)
        .Where(p => p.CanRead)
        .ToDictionary(
            p => dataTable2.FirstOrDefault(x => x.FieldName == p.Name)?.Description ?? p.Name,
            p => genAccessor(p)
        );

    var keys = props.Keys.ToList();

    var dt = new DataTable();
    // Add columns needed
    keys.ForEach(k => dt.Columns.Add(k));

    // Insert rows to table
    var eData = dataTable1.GetEnumerator();
    while (eData.MoveNext())
    {
        dt.Rows.Add(keys.Select(k => props[k](eData.Current)).ToArray());
    }
    return dt;
}

private class DataTable1
{
    public string Col1 { get; set; }
    public string Col2 { get; set; }
    public string Col3 { get; set; }
}

private class DataTable2
{
    public string FieldName { get; set; }
    public string Description { get; set; }
}
100% dynamic ;)
Raghunath Pentela7y ago

This i have to create every column seperately. But my columns are autogenerated.
Raghunath Pentela7y ago
Ok will try
Mario Scheeren7y ago
It should work somehow like this ... mybe Binding OneWay only:
Raghunath Pentela7y ago
Ok will see If i want to bind column header then ? With autogeneratedcolumns as true
Mario Scheeren7y ago
C# 6.0 ExpandoObject

You can build an Object with dynamically added properties.

So mapping an element of table1 and replace the name of the property by table 2 to create new Elements ( used in an ObservableCollection ) to be displayed in your datatable.

https://www.oreilly.com/learning/building-c-objects-dynamically

even better:

https://weblog.west-wind.com/posts/2012/feb/08/creating-a-dynamic-extensible-c-expando-object
Raghunath Pentela7y ago
Hi MarioWhat is expandoobject ? I want to bind header but with datagrid autogenerate columns as true and binded to viewmodel observationclass(table1) I am using entityframework model to fillup table1. Datarid autogeneratedcolumns should be true.
Mario Scheeren7y ago
Do you want to know how to bind a Column.Header? Or simply create new ExpandoObjects from the two Tables having the right propertynames?