Grouping in RadGridView

[Pavel]

Hi,

I have a problem with grouping data in RadGridView. I set IList as dataSource to RadGridView.
IList is a list of objects some class Product. Class Product has property Category which is a class with some fields too.

How can I set by what field of class Gategory group the data, when I grouping by Category column in Poduct ?



Any help would be appreciated!

Regards!

[Richard Slade]

Hi Pavel,

Have a look at the docs at this link in order to acheive grouping. The PropertyName of the GroupDescriptor needs to be the ColumnName.
E.g.

descriptor1.GroupNames.Add("ColumnName", ListSortDirection.Ascending)

Hope that helps, but let me know if you need more information
Richard

[Richard Slade]

Hello,

How did you get on with this? If it helped, please mark as answer. If you need more help, just let me know
Regards,
Richard

[Pavel]

Richard , thank you very much for your quick responses.
I tried this also but unfortunately, I could not solve the problem.
I can not understand how can I select necessary field in class Category to group Products.

Below is the code of my problem

01.public partial class Form1 : Form
02.    {
03.        public Form1()
04.        {
05.            InitializeComponent();
06.            radGridView1.DataSource = InitList();
07.        }
08.
09.        private List<Product> InitList()
10.        {
11.            List<Product> list = new List<Product>();
12.            var category1 = new Category() {Id = 1, CategoryName = "Category1"};
13.            var category2 = new Category() {Id = 2, CategoryName = "Category2"};
14.            list.Add(new Product()
15.                        {
16.                            Id = 1,
17.                            Name = "Product1",
18.                            ProductCategory = category1
19.                        });
20.            list.Add(new Product()
21.                        {
22.                            Id = 2,
23.                            Name = "Product2",
24.                            ProductCategory = category2
25.                        });
26.            list.Add(new Product()
27.                        {
28.                            Id = 3,
29.                            Name = "Product3",
30.                            ProductCategory = category1
31.                        });
32.            return list;
33.        }
34.
35.        class Product
36.        {
37.            public int Id { get; set; }
38.            public string Name { get; set; }
39.            public Category ProductCategory { get; set; }
40.        }
41.
42.        class Category
43.        {
44.            public int Id { get; set; }
45.            public string CategoryName { get; set; }
46.
47.            public override string ToString()
48.            {
49.                return CategoryName;
50.            }
51.        }
52.    }

When I group Product by column Category, all Products are in Category1 and Category2 is missing

[Richard Slade]

hello Pavel,

Please try this. this is grouped by "Name", the name of the column for the product.

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
        radGridView1.DataSource = InitList();
        radGridView1.EnableGrouping = true;
    }
    private void Form1_Load(object sender, EventArgs e)
    {
        GroupDescriptor descriptor = new GroupDescriptor();
        descriptor.GroupNames.Add("Name", ListSortDirection.Ascending);
        this.radGridView1.GroupDescriptors.Add(descriptor);
    }
    private List<Product> InitList()
    {
        List<Product> list = new List<Product>();
        var category1 = new Category() {Id = 1, CategoryName = "Category1"};
        var category2 = new Category() {Id = 2, CategoryName = "Category2"};
        list.Add(new Product()
                    {
                        Id = 1,
                        Name = "Product1",
                        ProductCategory = category1
                    });
        list.Add(new Product()
                    {
                        Id = 2,
                        Name = "Product2",
                        ProductCategory = category2
                    });
        list.Add(new Product()
                    {
                        Id = 3,
                        Name = "Product3",
                        ProductCategory = category1
                    });
        return list;
    }
}
    class Product
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public Category ProductCategory { get; set; }
    }
    class Category
    {
        public int Id { get; set; }
        public string CategoryName { get; set; }

        public override string ToString()
        {
            return CategoryName;
        }
    }

let me know if that helps
Richard

[Richard Slade]

Hi Pavel,

Did this help?
Thanks
Richard

[Richard Slade]

Hello,

If this helped, please remember to mark as answer so others can find the solution too.
regards,
Richard

[Pavel]

Sorry Richard, but it didn't help ! You didn't understand me correctly. In my task I need to group not by Name, but group by field Name of field Category.

[Richard Slade]

Pavel,

As far as I jnow, you'll need to link it via the Category Id, not the object. Please see the exmaple

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
        radGridView1.DataSource = InitList();
        radGridView1.EnableGrouping = true;
        RadControlSpyForm form = new RadControlSpyForm();
        form.Show();
    }
    private void Form1_Load(object sender, EventArgs e)
    {
        GroupDescriptor descriptor = new GroupDescriptor();
        descriptor.GroupNames.Add("ProductCategory", ListSortDirection.Ascending);
        this.radGridView1.GroupDescriptors.Add(descriptor);
    }
    private List<Product> InitList()
    {
        List<Product> list = new List<Product>();
        Category category1 = new Category() { Id = 1, CategoryName = "Category1" };
        Category category2 = new Category() { Id = 2, CategoryName = "Category2" };
        list.Add(new Product()
                    {
                        Id = 1,
                        Name = "Product1",
                        ProductCategory = 1
                    });
        list.Add(new Product()
                    {
                        Id = 2,
                        Name = "Product2",
                        ProductCategory = 2
                    });
        list.Add(new Product()
                    {
                        Id = 3,
                        Name = "Product3",
                        ProductCategory = 1
                    });
        return list;
    }
}
    class Product
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public int ProductCategory { get; set; }
    }
    class Category
    {
        public int Id { get; set; }
        public string CategoryName { get; set; }

        public override string ToString()
        {
            return CategoryName;
        }
    }

Hope that helps
Richard

[Pavel]

Hi, Richard !

If I understand correctly - you propose to replace the type of property from Category to Int and group by it?

I understand, that i can group by value-type.

Then, i must change my model only for display it in the grid?

It is possible to group by instance of custom type?

[Richard Slade]

Hi,

As far as I know, no. you must group by a value type.
Hope that helps
Richard

[Alexander]

Hi!

It is imporant feature, that i can group by instance of custom class.

Overriding "Equals" of custom class doesn't work.
How grouping works inside? It is hard-coded switch with cases for each value type? :) 
I hope it is not true, and "grouping engine" are more flexible. I'm sure, that set by which value-field of custom class instance do grouping, is it possible, because developers simply couldn't forget this possibility.

Maybe, someone, who are closer to development of this control can give answer?

Thanks for attention!

[Julian Benkov]

Hello Pavel,

You can implement this scenario by using sub-properties binding. Bind the Category column to the desired property of the Category object. This will allow you to apply grouping on this column, Please check the online help for sub-property binding and our Data manipulation example in our demo application.

I hope this was helpful. 

Richard thank you for your comments and assistance.

Greetings,
Julian Benkov
the Telerik team

[Alexander]

Thanks, Julian Benkov, it is working.

Answer is simple. For group by Product.Category.Name, you need to set FieldName of column to "Category.Name" :)

Can i bind column text to one property and column value to another? Such as DisplayMember and ValueMember in ComboBox.

For example, i need display Category.Name as column text, but group by Category.Id.

Thanks!

[Julian Benkov]

Hi Pavel,

You can not implement this behavior using properties such as DisplayMember, ValueMember valid for combobox control and column. To support this functionality you can create two columns and bind them to 'Category.Id' and "Category.Name". You can make the 'Category.Id' column invisible and execute the grouping operation using GroupDescriptors API:

this.radGridView1.Columns.Add("CategoryId", "Category Id", "Category.Id");
this.radGridView1.Columns.Add("CategoryName", "Category Name", "Category.Name");
this.radGridView1.Columns["CategoryId"].IsVisible = false;
this.radGridView1.GroupDescriptors.Expression = "CategoryId";

I hope this is helpful.

Kind regards,
Julian Benkov
the Telerik team