Set the proper globalization Tag in the web.config file.
Setting the Culture and UI Culture for Web Forms Globalization: By specifying a culture it is possible to use a set of common preferences for information like strings and date and number formats that correspond to users' cultural conventions.
globalization: Configures the globalization settings for an application.
Eg.
<configuration>
<system.web>
<globalization culture="en-US" uiCulture="en-US" />
</system.web>
</configuration>
culture: Specifies the default culture for processing incoming Web requests.
uiCulture: Specifies the default culture for processing locale-dependent resource searches.