🐛 修复一些问题

Plain Craft Launcher 2/Modules/Base/ModValidate.vb

@@ -314,6 +314,7 @@ End Class
 Public Class ValidateFolderPath
     Inherits Validate
     Public Property UseMinecraftCharCheck As Boolean = True
+    Public Property AllowNull As Boolean = False
     Public Sub New()
     End Sub
     Public Sub New(UseMinecraftCharCheck As Boolean)
@@ -325,9 +326,9 @@ Public Class ValidateFolderPath
         If Not Str.TrimEnd("\").EndsWithF(":") Then Str = Str.TrimEnd("\")
         '检查是否为空
         Dim LengthCheck As String = New ValidateNullOrWhiteSpace().Validate(Str)
-        If Not LengthCheck = "" Then Return LengthCheck
+        If Not AllowNull AndAlso Not LengthCheck = "" Then Return LengthCheck
         '检查长度
-        LengthCheck = New ValidateLength(1, 254).Validate(Str)
+        LengthCheck = New ValidateLength(If(AllowNull, 0, 1), 254).Validate(Str)
         If Not LengthCheck = "" Then Return LengthCheck
         '检查开头
         If Str.StartsWithF("\\Mac\") Then GoTo Fin

Plain Craft Launcher 2/Modules/Minecraft/ModModpack.vb

@@ -987,9 +987,11 @@ Retry:
 
             '步骤 1：从 Modrinth 获取 Mod 工程信息，得到 URL
             Dim Mods As New List(Of McMod)
-            For Each m In Directory.EnumerateFiles(Version.Path & "mods\")
-                If m.EndsWithF(".jar") Then Mods.Add(New McMod(m))
-            Next
+            If Directory.Exists(Version.Path & "mods\") Then
+                For Each m In Directory.EnumerateFiles(Version.Path & "mods\")
+                    If m.EndsWithF(".jar") Then Mods.Add(New McMod(m))
+                Next
+            End If
 
             '从 Modrinth 获取信息
             Dim ModrinthHashes = Mods.Select(Function(m) m.ModrinthHash).ToList()