Add pageNumber param.

Lombiq.HelpfulLibraries.OrchardCore/Data/QueryExtensions.cs

@@ -160,25 +160,35 @@ public static async Task<GetPageAndPagerViewModel<T>> GetPageAndPagerAsync<T>(
     /// <c>Pager</c> shape that can be used to navigate to other pages.
     /// </summary>
     /// <param name="httpContext">Used to source some required services and current request information.</param>
+    /// <param name="pageNumber">
+    /// If not <see langword="null"/>, it's used to configure the <see cref="PagerParameters"/>. Otherwise the query
+    /// value of <c>pagenum</c> is used from <paramref name="httpContext"/>.
+    /// </param>
     /// <param name="defaultPageSize">
     /// An optional value it you want custom page size instead of the value coming from <see cref="ISite.PageSize"/>.
     /// </param>
     public static Task<GetPageAndPagerViewModel<T>> GetPageAndPagerAsync<T>(
         this IQuery<T> query,
         HttpContext httpContext,
+        int? pageNumber = null,
         int? defaultPageSize = null)
         where T : class
     {
+        var page = pageNumber ?? 0;
+        if (page <= 0)
+        {
+            page = httpContext.Request.Query.TryGetValue("pagenum", out var pageNumberString) &&
+                   int.TryParse(pageNumberString, CultureInfo.InvariantCulture, out var pageNumberInt)
+                ? pageNumberInt
+                : 1;
+        }
+
         var provider = httpContext.RequestServices;
-        var pageNumber = httpContext.Request.Query.TryGetValue("pagenum", out var pageNumberString) &&
-                         int.TryParse(pageNumberString, CultureInfo.InvariantCulture, out var pageNumberInt)
-            ? pageNumberInt
-            : 1;
 
         return query.GetPageAndPagerAsync(
             provider.GetRequiredService<IShapeFactory>(),
             provider.GetRequiredService<ISiteService>(),
-            new PagerParameters { Page = pageNumber > 0 ? pageNumber : 1 },
+            new PagerParameters { Page = page > 0 ? page : 1 },
             httpContext.Request.RouteValues,
             defaultPageSize);
     }