I noticed that code which had been working for a long time stopped functioning after updating to version 5.0.1.
It works correctly in version 4.3.17.
I created a test project as an example; you can take a look at it.
DTOs
public class Category1Info
{
public int Id { get; set; }
public string Name { get; set; }
}
public class Category2Info
{
public int Id { get; set; }
public string Name { get; set; }
}
public class ProductInfo
{
public int Category1 { get; set; }
public int Category2 { get; set; }
public string Name { get; set; }
public List<string> Colors { get; set; } = [];
}
DefaultViewModel.cs
public class DefaultViewModel : MasterPageViewModel
{
public List<ProductInfo> Products { get; set; }
public List<Category1Info> Categories1 { get; set; }
public List<Category2Info> Categories2 { get; set; }
public DefaultViewModel()
{
}
public override async Task Load()
{
if (!Context.IsPostBack)
{
Categories1 =
[
new() { Id = 1, Name = "C1-1" },
new() { Id = 2, Name = "C1-2" },
new() { Id = 3, Name = "C1-3" }
];
Categories2 =
[
new() { Id = 10, Name = "C2-10" },
new() { Id = 11, Name = "C2-11" },
new() { Id = 12, Name = "C2-12" }
];
Products =
[
new() { Name = "Product 1", Category1 = 1, Category2 = 10, Colors = ["Red"] },
new() { Name = "Product 2", Category1 = 2, Category2 = 11, Colors = ["Green", "Yellow"] },
new() { Name = "Product 3", Category1 = 3, Category2 = 12, Colors = ["Orange"] }
];
}
await base.Load();
}
}
Default.dothtml
@viewModel DotvvmApplication1.ViewModels.DefaultViewModel, DotvvmApplication1
@masterPage Views/MasterPage.dotmaster
<dot:Content ContentPlaceHolderID="MainContent">
<table border="1">
<thead>
<tr>
<th></th>
<dot:Repeater DataSource="{value: _root.Categories1}" RenderWrapperTag="false">
<th>{{value: Name}}</th>
</dot:Repeater>
</tr>
</thead>
<tbody>
<dot:Repeater DataSource="{value: _root.Categories2}" RenderWrapperTag="false">
<tr>
<th>
{{value: Name}}
</th>
<dot:Repeater DataSource="{value: _root.Categories1}" RenderWrapperTag="false">
<td>
<dot:Repeater DataSource="{value: _root.Products.FirstOrDefault(x => x.Category1 == _this.Id && x.Category2 == _parent.Id).Colors}"
RenderWrapperTag="false">
<ItemTemplate>
{{value: _this}}
</ItemTemplate>
<SeparatorTemplate>
,
</SeparatorTemplate>
</dot:Repeater>
</td>
</dot:Repeater>
</tr>
</dot:Repeater>
</tbody>
</table>
</dot:Content>
v4.3.17 
v5x 
Uncaught TypeError: Unable to process binding "template: function(){return { foreach:Categories2,name:"j2AN3jFFJJra3mH1+4t7bgvcgox0TNtvd9HrwOPf+Bg="} }"
Message: Unable to process binding "template: function(){return { foreach:$parent.Categories1,name:"SWfhroGYkcVLAM3Th5gv2Fe8JHE/y7xFKxH4dnGZqNY="} }"
Message: Unable to process binding "template: function(){return { foreach:$parents[1].Products()?.find((x) => ko.unwrap(x).Category1() == Id() && ko.unwrap(x).Category2() == $parent.Id())()?.Colors,name:"WCyHKNTyHWi0zmm4cP/xF1ot+hUXoeVQSfQO9ZB3rMs=",separatorTemplate:"yUtsycAMplDRuAJkWHWZIr0gZBB9cBFTgoXieKvdvpI="} }"
Message: $parents[1].Products(...)?.find(...) is not a function
at template (eval at createBindingsStringEvaluator (knockout:3248:16), :3:191)
at evaluateValueAccessor (knockout:3521:16)
at knockout:3698:32
at init (knockout:6166:58)
at knockout:3757:46
at Object.ignore (knockout:1618:33)
at knockout:3756:48
at Object.arrayForEach (knockout:205:24)
at applyBindingsToNodeInternal (knockout:3742:22)
at applyBindingsToNodeAndDescendantsInternal (knockout:3600:44)
The problematic code is this:
_root.Products.FirstOrDefault(x => x.Category1 == _this.Id && x.Category2 == _parent.Id).Colors
i
DefaultViewModel.cs (1.3 KB)
Default.dothtml (1.5 KB)
ProductInfo.cs (487 Bytes)