I have added targetFramework=”4.5” to httpRunTime in web.config to solve the issue given in below reference blog link below.

https://www.toshalinfotech.com/Blogs/ID/131/Finding-solutions-on-Period-got-missing-from-url

This has fixed the issue of period got missing from URI but it lead me to face many other issues.

To understand all the issues, first you need to understand what exactly does .netframe behavior when we add <httpRuntime targetFramework="4.5" /> to our application.

<httpRuntime targetFramework="4.5" /> is a shortcut that allows the ASP.NET runtime to infer a wide array of configuration settings. If the runtime sees this setting, it will expand it out just as if you had written the following:

<configuration>

  <appSettings>

    <add key="aspnet:UseTaskFriendlySynchronizationContext" value="true" />

    <add key="ValidationSettings:UnobtrusiveValidationMode" value="WebForms" />

  </appSettings>

    <system.web>

      <compilation targetFramework="4.5" />

      <machineKey compatibilityMode="Framework45" />

      <pages controlRenderingCompatibilityVersion="4.5" />

    </system.web>

</configuration>

To find detailed explanation click here

Problems faced:

1. <add key="aspnet:UseTaskFriendlySynchronizationContext" value="true"/>

Do not simply adjust this setting as it can lead to deadlocks! Where your code worked before, it may not work after - see below for a discussion.

Solution:

My system had some 3rd party asynchronous calls to make. And because of aspnet:UseTaskFriendlySynchronizationContext changed to true, all 3rd party post asynchronous calls were broken. As I have to make no changes to existing code, I had to add <add key="aspnet:UseTaskFriendlySynchronizationContext" value="false" /> to appsettings.

Problems faced:

1. Client side validators work differently in ASP.Net 4.5. Microsoft calls it Unobtrusive Validation Mode, and they are using jQuery (2.0) for this.

Telerik Controls 2013 Q1 SP2 are also using jQuery (but still version 1.9)

Solution:

The problem is when using scriptmanager, or RadScriptmanager, after loading the telerik jQuery libraries, client side validations do not work any more. This took me some hours, looking at all kinds of possible solutions, but finally the most simple solution is disabling the new functionality by adding a setting in Web.config

<add key="ValidationSettings:UnobtrusiveValidationMode" value="None"/>

So since jQuery looks to be standard in asp.net 4.5, it would be a good thing if Telerik would use the same libraries.