合并-bug修复，17723 ：文件页面范围不合理时，不应该允许进行合并操作

PDF Office/ViewModels/Dialog/ToolsDialogs/MergeDialogViewModel.cs

@@ -280,12 +280,41 @@ namespace PDF_Master.ViewModels.Dialog.ToolsDialogs
 
         private void Merge()
         {
+            
             bool result = true;
-            CPDFDocument SaveDoc = CPDFDocument.CreateDocument();
+            CPDFDocument SaveDoc = CPDFDocument.CreateDocument();
+
+            for (int i = 0; i < MergeObjectlist.Count; i++)
+            {
+                List<int> listnum = new List<int>();
+                if (MergeObjectlist[i].SetPageRange == null || MergeObjectlist[i].SetPageRange.Count == 0)
+                {
+                    AlertsMessage alertsMessage = new AlertsMessage();
+                    alertsMessage.ShowDialog("", App.MainPageLoader.GetString("PageRangeWarning"), App.ServiceLoader.GetString("Text_ok"));
+                    return;
+                }
+            }
+            for (int i = 0; i < MergeObjectlist.Count; i++)
+            {
+                List<int> listnum = new List<int>();
+                if (MergeObjectlist[i].SetPageRange == null || MergeObjectlist[i].SetPageRange.Count == 0)
+                {
+                    AlertsMessage alertsMessage = new AlertsMessage();
+                    alertsMessage.ShowDialog("", App.MainPageLoader.GetString("PageRangeWarning"), App.ServiceLoader.GetString("Text_ok"));
+                    return;
+                }
+            }
+               
             for (int i = 0; i < MergeObjectlist.Count; i++)
-            {
-                //图片
-                if (Path.GetExtension(MergeObjectlist[i].FilePath).Trim().ToLower() != ".pdf")
+            {
+                if (MergeObjectlist[i].SetPageRange == null)
+                {
+                    AlertsMessage alertsMessage = new AlertsMessage();
+                    alertsMessage.ShowDialog("", App.MainPageLoader.GetString("PageRangeWarning"), App.ServiceLoader.GetString("Text_ok"));
+                }
+
+                    //图片
+                    if (Path.GetExtension(MergeObjectlist[i].FilePath).Trim().ToLower() != ".pdf")
                 {
                     if (Path.GetExtension(MergeObjectlist[i].FilePath).Trim().ToLower() == ".gif")
                     {//GIF下面方法产生虚影改成与图片转PDF一致