Using C# code to add Permission Level To SharePoint User Group

In this post I'm going to discuss how you can add a permission level (Read, Contribute, Full Control, etc) to a SharePoint user group. Here is a sample code,

public void addPermissionToGroup()

{

    SPSite site = new SPSite("Site URL");

    SPWeb spWeb = site.OpenWeb();

    string permissionName = "Read";

    string groupName = "Project Manager";

    try

    {

        spWeb.AllowUnsafeUpdates = true;

        SPRoleAssignment roleAssignment = new SPRoleAssignment(spWeb.SiteGroups[groupName]);

        roleAssignment.RoleDefinitionBindings.Add(spWeb.RoleDefinitions[permissionName]);

        if (!spWeb.HasUniqueRoleAssignments)

            spWeb.BreakRoleInheritance(false);

        spWeb.RoleAssignments.Add(roleAssignment);

        spWeb.Update();

    }

    catch (Exception _exception)

    {

        throw _exception;

    }

    finally

    {

        spWeb.AllowUnsafeUpdates = false;

    }

}

You can view RoleDefinitions defined for your site by navigating to
Site Settings --> Advanced Permissions.