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kb(grid): Revamp KB for column header alignment in hierarchy (#1970)
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Co-authored-by: Dimo Dimov <[email protected]>
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github-actions[bot] and dimodi authored Mar 12, 2024
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254 changes: 141 additions & 113 deletions knowledge-base/grid-align-columns-hierarchy.md
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---
title: Align Columns in Hierarchical Grid
description: How to align columns in nested detail template of a hierarchical grid.
title: Align Column Headers in Grid Hierarchy
description: How to align column headers in the nested detail template of a hierarchy Grid.
type: how-to
page_title: Align Columns in Hierarchical Grid
page_title: How to Align Columns Headers at Different Grid Hierarchy Levels
slug: grid-kb-align-columns-hierarchy
position:
tags:
ticketid: 1468988
ticketid: 1468988, 1522877, 1644195
res_type: kb
---

## Environment

<table>
<tbody>
<tr>
<td>Product</td>
<td>Grid for Blazor</td>
</tr>
</tbody>
<tbody>
<tr>
<td>Product</td>
<td>Grid for Blazor</td>
</tr>
</tbody>
</table>


## Description
I want to showcase hierarchical data in the grid and to make the DetailTemplate columns match the main column headers.

## Solution
While generally a task for a treelist type of component, you can show self-referencing data in a grid through its detail templates and if the field names match, you can even use the only the headers from the main grid.
This KB article answers the following questions:

To align the columns of nested grid detail templates, you need to:
* How to configure a hierarchy Grid and make the `DetailTemplate` Grid column headers align with the master Grid column headers?
* How to define the detail Grid columns, so that they match the master Grid columns?
* How to align the column borders of nested child Grids with the column borders of the parent Grid?

## Solution

* set a width to the grid that matches the width of its columns
* set width to the columns of the nested grids that match the column widths of the main grid
* the first column of each child grid must have width smaller than the first column of the main grid with the size of the hierarchy expand column times the levels of hierarchy that you have
* add styles that remove the scrollbars from the grid to clean out the UI and reduce distortions that they can cause
* optionally, hide the headers of the nested grids
The best reason to align Grid column headers across hierarchy levels is when the Grid displays a self-referencing hierarchy. There are two ways to achieve the desired appearance and aligned columns:

>caption The result from the code snippet below
* Use a [TreeList component]({%slug treelist-overview%}). It may be a better option than the Grid, because the TreeList supports a random number of hierarchy levels and there is no need to define and configure each level separately. The TreeList uses the same column and column header for each data item property at any level.
* Use a Grid with [additional CSS code]({%slug themes-override%}) to align the columns at all hierarchy levels.

![Align Hierarchical Grid Columns](images/grid-align-hierarchical-columns.png)
The steps below describe how to align columns when using a Grid hierarchy.

1. Set a [custom CSS `Class`]({%slug grid-overview%}#grid-parameters) to the master (parent) Grid, so that the custom styles do not affect other Grid instances.
1. Use the custom CSS class to:
1. Remove the padding of the `DetailTemplate` container (`td.k-detail-cell`).
1. Disable the vertical scrollbar of the Grid data area (`div.k-grid-content`).
1. Remove the empty space in the Grid header area, which is above the vertical scrollbar (`div.k-grid-header`).
1. Remove the right border of the detail Grids (`.k-grid`).
1. Set the same column `Width` to the columns from all hierarchy levels, that should align with one another.
1. Set widths to all columns, except the first one of each Grid. This will allow the first column to expand and collapse automatically, depending on the hierarchy level and the available space.
1. If the number of hierarchy levels is greater than two, use [named `context` variables for the Grid `DetailTemplate`]({%slug nest-renderfragment%}).
1. (optional) Remove the header area of the detail Grids. This makes sense only if the detail Grids have no enabled features that rely on column headers, for example, sorting or filtering.

>caption Align the columns in hierarchical grids
````CSHTML
@* Three levels of grids - note how the first columns of the nested grids have the width of the detail expand cell subtracted twice
for the Default Theme, it is 2*32px but that can vary between themes and based on the font-size of the page.
Also, the main grid has a width that matches closely the sum of the column widths and the horizontal scrollbars
are hidden in order to produce cleaner UX *@
<TelerikGrid Data="@GridData.Where(x => x.ParentId == null)"
TItem="@GridItem"
OnStateInit="@OnGridStateInit"
Class="align-hierarchy">
<GridToolBarTemplate>
<label><TelerikCheckBox @bind-Value="@HideDetailHeaders" /> Hide Detail Grid Headers</label>
</GridToolBarTemplate>
<GridColumns>
<GridColumn Field="@nameof(GridItem.Text)" />
<GridColumn Field="@nameof(GridItem.Quantity)"
Width="120px" />
<GridColumn Field="@nameof(GridItem.Date)"
Width="260px"
DisplayFormat="{0:D}" />
</GridColumns>
<DetailTemplate Context="contextLevel1">
<TelerikGrid Data="@GridData.Where(x => x.ParentId == contextLevel1.Id)">
<GridColumns>
<GridColumn Field="@nameof(GridItem.Text)" />
<GridColumn Field="@nameof(GridItem.Quantity)"
Width="120px" />
<GridColumn Field="@nameof(GridItem.Date)"
Width="260px"
DisplayFormat="{0:D}" />
</GridColumns>
<DetailTemplate Context="contextLevel2">
<TelerikGrid Data="@GridData.Where(x => x.ParentId == contextLevel2.Id)">
<GridColumns>
<GridColumn Field="@nameof(GridItem.Text)" />
<GridColumn Field="@nameof(GridItem.Quantity)"
Width="120px" />
<GridColumn Field="@nameof(GridItem.Date)"
Width="260px"
DisplayFormat="{0:D}" />
</GridColumns>
</TelerikGrid>
</DetailTemplate>
</TelerikGrid>
</DetailTemplate>
</TelerikGrid>
<style>
/* remove the default padding from the detail template cell to facilitate column alignment */
.no-detail-padding.k-grid .k-detail-cell {
/* remove the DetailTemplate container padding */
.align-hierarchy td.k-table-td.k-detail-cell {
padding: 0;
}
/* */
.no-detail-padding.k-grid .k-detail-cell .k-header {
display: none;
}
/* hide horizontal scrollbars on the grids to produce cleaner UI for the user */
.no-detail-padding.k-grid .k-grid-content {
overflow-x: hidden;
/* remove the vertical Grid scrollbars */
.align-hierarchy .k-grid-content {
overflow-y: visible;
}
/* hide vertical scrollbars to simplify UI, also reduces the chance of mismatch between column headers */
.no-detail-padding.k-grid > .k-grid-header {
padding-right: 0 !important;
/* remove the empty space above the vertical Grid scrollbar */
.align-hierarchy .k-grid-header {
padding-inline-end: 0;
}
.no-detail-padding.k-grid .k-grid-content {
overflow-y: hidden;
/* remove the detail Grid right border */
.align-hierarchy .k-grid {
border-right-width: 0;
}
</style>
<TelerikGrid Data="@MainLevelsData" Class="no-detail-padding" Width="820px" Pageable="true">
<GridColumns>
<GridColumn Field="Id" Width="200px"></GridColumn>
<GridColumn Field="Field1" Width="300px"></GridColumn>
<GridColumn Field="Field2" Width="300px"></GridColumn>
</GridColumns>
<DetailTemplate Context="firstLevelItem">
@{
var currGridData = GetLevelData(firstLevelItem.Id);
<TelerikGrid Data="@currGridData" Pageable="true" PageSize="5">
<GridColumns>
<GridColumn Field="Id" Width="168px"></GridColumn>
<GridColumn Field="Field1" Width="300px"></GridColumn>
<GridColumn Field="Field2" Width="300px"></GridColumn>
</GridColumns>
<DetailTemplate Context="secondLevelItem">
@{
var currGridData = GetLevelData(secondLevelItem.Id);
<TelerikGrid Data="@currGridData" Pageable="true" PageSize="5">
<GridColumns>
<GridColumn Field="Id" Width="168px"></GridColumn>
<GridColumn Field="Field1" Width="300px"></GridColumn>
<GridColumn Field="Field2" Width="300px"></GridColumn>
</GridColumns>
</TelerikGrid>
}
</DetailTemplate>
</TelerikGrid>
@if (HideDetailHeaders)
{
<style>
/* remove the detail Grid column headers */
.align-hierarchy .k-grid .k-grid-header {
display: none;
}
</DetailTemplate>
</TelerikGrid>
</style>
}
@code {
List<SelfReferencingHierarchyModel> MainLevelsData { get; set; }
List<SelfReferencingHierarchyModel> AllData { get; set; }
private List<GridItem> GridData { get; set; } = new();
private bool HideDetailHeaders { get; set; }
public class SelfReferencingHierarchyModel
private void OnGridStateInit(GridStateEventArgs<GridItem> args)
{
public int Id { get; set; }
public int? ParentId { get; set; }
public string Field1 { get; set; }
public string Field2 { get; set; }
// Expand the master Grid rows automatically
args.GridState.ExpandedItems = GridData.Where(x => x.ParentId == null).ToList();
}
protected override void OnInitialized()
{
AllData = new List<SelfReferencingHierarchyModel>();
GridData = LoadFlat();
base.OnInitialized();
}
#region Grid Data Generation
private const int TreeLevels = 3;
private int RootItems { get; set; } = 2;
private int ItemsPerLevel { get; set; } = 2;
private int IdCounter { get; set; } = 1;
private List<GridItem> LoadFlat()
{
List<GridItem> items = new List<GridItem>();
//generate top level items
for (int i = 0; i < 35; i++)
PopulateChildren(items, null, 1);
return items;
}
private void PopulateChildren(List<GridItem> items, int? parentId, int level)
{
var itemCount = level == 1 ? RootItems : ItemsPerLevel;
for (int i = 1; i <= itemCount; i++)
{
AllData.Add(new SelfReferencingHierarchyModel
var itemId = IdCounter++;
items.Add(new GridItem()
{
Id = i,
Field1 = $"main level {i}",
Field2 = $"main level field 2 - {i}"
Id = itemId,
ParentId = parentId,
Text = $"Level {level} Item {i}",
Quantity = Random.Shared.Next(0, 1000),
Date = new DateTime(Random.Shared.Next(2000, 2030), Random.Shared.Next(1, 13), Random.Shared.Next(1, 29))
});
for (int j = 0; j < 12; j++)
if (level < TreeLevels)
{
//generate first level items - note the Id and ParentId logic
AllData.Add(new SelfReferencingHierarchyModel
{
Id = 100 + j,
ParentId = i,
Field1 = $"first level {j}",
Field2 = $"first level field 2 - {j}"
});
for (int k = 0; k < 12; k++)
{
//generate second level items - note the Id and ParentId logic
AllData.Add(new SelfReferencingHierarchyModel
{
Id = 6000 * j + k, // does not really produce unique IDs here, but for this sample it does not matter
ParentId = 100 + j,
Field1 = $"second level {j}",
Field2 = $"second level field 2 - {j}"
});
}
PopulateChildren(items, itemId, level + 1);
}
}
MainLevelsData = AllData.Where(itm => itm.ParentId == null).ToList();
}
List<SelfReferencingHierarchyModel> GetLevelData(int parentId)
#endregion Grid Data Generation
public class GridItem
{
return AllData.Where(itm => itm.ParentId == parentId).ToList();
public int Id { get; set; }
public int? ParentId { get; set; }
public string Text { get; set; } = string.Empty;
public int Quantity { get; set; }
public DateTime Date { get; set; }
}
}
````

## See Also


* [Grid Hierarchy]({%slug components/grid/features/hierarchy%})
* [Using custom CSS with Telerik Blazor components]({%slug themes-override%})
* [TreeList component documentation]({%slug treelist-overview%})
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