<TelerikButton Icon ="calendar" - calendar does not exist in the current context

[Karthik]

<div class="btn-toolbar mb-2 mb-md-0">
            <div class="btn-group mr-2">
                <TelerikButton  Icon="Calendar" Primary="true"  OnClick="@(_ => DateRangeFilter(3))">3 Months</TelerikButton>

 Icon="Calendar" Primary="true" - both of the properties tell it does not exist in the current context.

               

[Georgi]

Hello, Karthik,

Based on the Button configuration, I understand you might be upgrading from an older version.

There were breaking changes to the Icons in version 4.0.0. Due to this, currently, the Icon parameter accepts a member of the FontIcon enum or a property of the static SvgIcon class and it is set like this:

<TelerikButton Icon="@FontIcon.Calendar">Font Icon</TelerikButton>

<TelerikButton Icon="@SvgIcon.Calendar">SVG Icon</TelerikButton>

Additionally, the IconClass was removed in version 4.0.0. Currently, to use a custom icon, you can create a CSS class and then pass it to the Icon parameter:
<style>
    .my-icon {
        /* define a background image or a custom font icon here */
        background: purple;
        /* dimensions and other base styles will usually come from another class */
        width: 1em;
        height: 1em;
        font-size: 16px;
    }
</style>

<TelerikButton Icon="@( "my-icon" )">Custom Icon</TelerikButton>
Lastly, due to the breaking changes in 3.0.0, the Primary parameter was removed in favour of ThemeColor of type string. You can use the old primary Button styling like this:
<TelerikButton  Icon="@SvgIcon.Calendar" ThemeColor="primary">3 Months</TelerikButton>
Let me know if additional assistance is required. 

Regards,
Georgi
Progress Telerik