At the moment, when tabs hide their components are removed, so when you go back to a tab, it initializes again  - for example, the OnInitializedAsync event fires where you fetch data, so you have to fetch the data again.

This behavior should be controlled through a property so one can keep the original behavior where the components are cleared from the DOM and memory.

Perhaps an option can be added where tabs are initialized not on initial load, but upon first activation only. Maybe the feature can become something like an enum - LoadMode="InitialRender|FirstRender|EveryRender" (working title off the top of my head).

At the moment, a solution you can use is to send the data to the tab from its contents through an event, and to pass it to them as a Parameter so you can check for it before fetching data.

At the moment, if I have many tabs, their titles go off the screen (or the container of the tab strip). I want that they don't stretch my layout, or they don't become invisible.

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ADMIN EDIT

For the time being, there are two workarounds you can consider:

• adding a scrollbar to the tabs list:
  

  <style>
      /* sample settings for the parent of the tab strip to showcase how the rules below work */
      .tab-container {
          border: 1px solid red;
          width: 30%;
      }
      
      /* tab titles will now produce a scrollbar when too wide */
      .tab-container .k-tabstrip .k-tabstrip-items {
          flex-flow: inherit;
          max-width: 100%;
          overflow-x: auto;
          overflow-y: hidden;
      }
  
      /* just to showcase what happens when the content is wide - a separate scrollbar */
      .wide-content {
          background: yellow;
          width: 1200px;
      }
  </style>
  
  <div class="tab-container">
      <TelerikTabStrip>
          @foreach (var item in Enumerable.Range(1, 10))
          {
              <TabStripTab Title="@( $"Item {item}" )"><div class="wide-content">Content for item @item</div></TabStripTab>
          }
      </TelerikTabStrip>
  </div>

  
  
• making the tabs drop into multiple rows:

  <style>
      /* sample settings for the parent of the tab strip to showcase how the rules below work */
      .tab-container {
          border: 1px solid red;
          width: 30%;
      }
  
          /* tabs will wrap on more than one row if there are too many to fit */
          .tab-container .k-tabstrip .k-tabstrip-items {
              flex-wrap:wrap;
          }
  </style>
  
  <div class="tab-container">
      <TelerikTabStrip>
          @foreach (var item in Enumerable.Range(1, 10))
          {
              <TabStripTab Title="@( $"Item {item}" )"><div class="wide-content">Content for item @item</div></TabStripTab>
          }
      </TelerikTabStrip>
  </div>

---

I have four tabs in my tab strip, and the content in each tab is of varying width. The tab item resizes to the width of the content as it changes. I want to be able to set a fixed width for all the tabs so they don't expand and contract all the time.

===========

ADMIN EDIT

===========

In the meantime, you can control the width of the TabStrip with some custom CSS. You can use its Class parameter to set a custom CSS class to the main wrapping container of the component and then apply the desired styles. Thus, you will be styling only this specific instance of the TabStrip and not all instances on the page/app (in case needed, you can of course add the same CSS class to all instances to have the same styles).

The sample below demonstrates the described approach. First instance of the TabStrip has the default setup, no additional styles added. Second instance has fixed width.

<TelerikTabStrip>
    <TabStripTab Title="First">
        First tab content. Go to the third tab to see the problem.
    </TabStripTab>
    <TabStripTab Title="Second tab heading longer than others">
        Second tab content. Go to the third tab to see the problem.
    </TabStripTab>
    <TabStripTab Title="Third">
        <div style="width: 2000px;">lorem ipsum</div>Third tab content.
    </TabStripTab>
</TelerikTabStrip>

<style>
    .tab-with-width {
        width: 600px;
    }
</style>

<TelerikTabStrip Class="tab-with-width">
    <TabStripTab Title="First">
        First tab content. Go to the third tab to see the behavior when the TapSrtrip has fixed width.
    </TabStripTab>
    <TabStripTab Title="Second tab heading longer than others">
        Second tab content. Go to the third tab to see the behavior when the TapSrtrip has fixed width.
    </TabStripTab>
    <TabStripTab Title="Third">
        <div style="width: 2000px;">lorem ipsum</div>Third tab content.
    </TabStripTab>
</TelerikTabStrip>

I want to style my tab headers with something similar to this, but it does not compile:

 <h2>Telerik Tab Strip</h2>
    <TelerikTabStrip TabPosition="Telerik.Blazor.TabPosition.Top">
        <TabStripTab Class="WeirdTab" Title="First">
            First tab content.
        </TabStripTab>
        <TabStripTab Title="Second">
            Second tab content.
        </TabStripTab>
        <TabStripTab Title="Third">
            Third tab content.
        </TabStripTab>
    </TelerikTabStrip>
    <style>
        .WeirdTab {
            color: red;
        }
    </style>

While I can style the content of the tabs in the tabs themlselves (see below) I'd like to be able to style the headers too

<h2>Telerik Tab Strip</h2>
<TelerikTabStrip TabPosition="Telerik.Blazor.TabPosition.Top">
    <TabStripTab Title="First">
        <div class="WeirdTab">
            First tab content.
        </div>
    </TabStripTab>
    <TabStripTab Title="Second">
        Second tab content.
    </TabStripTab>
    <TabStripTab Title="Third">
        Third tab content.
    </TabStripTab>
</TelerikTabStrip>
<style>
    .WeirdTab {
        color: red;
    }
</style>

The ActiveTabIndex parameter can take a value -1 to denote that no tab should be selected. This can plug into the current two-way binding as well.

At the moment, you can't get the currently active tab with code, the Title property of the tabs is not public.

Ideally, something like this should work:

ADMIN EDIT: As of October 2023, the TabStrip supports getting and setting the active tab with the ActiveTabIndex parameter. This request was marked as Complete when we exposed a Title parameter for the TabStripTab component. Enhanced programmatic access to TabStrip tab IDs can be implemented as part of TabStrip dynamic (closable) tabs.