Question

I have three tables as follows: table 1 is called Cat1, table 2 is called subcat1 and table three is called itemsTb. I have created relationships like this:

cat1 to subcat1 (one-to-many)
cat1 to itemstb (one-to-many)
subcat1 to itemstb (one-to-many)

I would like to display items in asp.net repeaters like this:

cat 1....
   ....item 1
   ....item 2
   ....item 3
cat 2
   subcat 1 .....
      .....item 1
      .....item 2
      .....item 3
cat 3.....
   ....item 1
   ....item 2

etc.

The schema of my tables is like this:

Table: cat
columns:
id      int
title   varchar

table  subcat
columns:
id     int
catid  int
title  varchar

table: items
columns
id         int
catid      int
subcatid   int
title      varchar

Anyone has any idea how can I display them using asp.net repeaters? Or do I have to structure my tables differently to make it work? Thanks a lot for your help.

Answer 1

All of the ASP.NET databound controls (Repeater, ListView, GridView, etc.) can use declarative data-binding for their DataSource. This isn’t very well documented IMO, but you can do something like:

<asp:Repeater ID="rptCategory">
    <ItemTemplate>
        <asp:Repeater ID="rptSubcategory" DataSource='<%#Eval("Subcategories")%>'>
             <ItemTemplate>
                <asp:Repeater ID="rptItems" DataSource='<%#Eval("Items")%>'>
                    <ItemTemplate>
                        <%#Eval("Name")%>
                    </ItemTemplate>
                </asp:Repeater>
             </ItemTemplate>
        </asp:Repeater>
    </ItemTemplate>
</asp:Repeater>

The specifics of what you need to bind to the DataSource property depends on what your initial data (the one that rptCategory is bound to).

If it’s a DataSet, then you need to build DataRelations and use the name of the appropriate DataRelation.

If it’s a C# object, then you’ll want to use the name of a collection property.

EDIT: Specifics on this particular schema follow….

For your schema, you would need 2 nested repeaters – 1 to handle the items and 1 to handle the subcategories (which would have another nested repeater for its items).

Using DataSets, you could do something like (note this is rough code, you’ll need to fill in some of the missing steps):

var ds = ExecuteDataSet(
   @"SELECT Id, Title FROM Cat;
   SELECT Id, CatId, Title FROM SubCat;
   SELECT Id, CatId, SubCatId, Title FROM Items;"
);
ds.DataRelations.Add("Cat_SubCat", ds.Tables["Cat"].Columns["Id"], ds.Tables["SubCat"].Columns["CatId"]);
ds.DataRelations.Add("Cat_Items", ds.Tables["Cat"].Columns["Id"], ds.Tables["Items"].Columns["CatId"]);
ds.DataRelations.Add("SubCat_Items", ds.Tables["SubCat"].Columns["Id"], ds.Tables["Items"].Columns["SubCatId"]);

this.rptCategory.DataSource = ds;
this.rptCategory.DataBind();

<asp:Repeater ID="rptCategory">
    <ItemTemplate>
        <h2>Category <%#Eval("Title")%></h2>
        <asp:Repeater ID="rptCatItems" DataSource='<%#Eval("Cat_Items")%>'>
            <ItemTemplate>
                <h4>Item (Category) <%#Eval("Title")%></h4>
            </ItemTemplate>
        </asp:Repeater>
        <asp:Repeater ID="rptCatSubCat" DataSource='<%#Eval("Cat_SubCat")%>'>
            <ItemTemplate>
                <h3>SubCategory <%#Eval("Title")%></h3>
                <asp:Repeater ID="rptSubCatItems" DataSource='<%#Eval("SubCat_Items")%>'>
                    <ItemTemplate>
                        <h4>Item (SubCategory) <%#Eval("Title")%></h4>
                    </ItemTemplate>
                </asp:Repeater>
            </ItemTemplate>
        </asp:Repeater>
    </ItemTemplate>
</asp:Repeater>