update

Author: SmartLinli

QuickDemo/6.Table_GridView/Table_GridView.sln

@@ -3,7 +3,7 @@ Microsoft Visual Studio Solution File, Format Version 12.00
 # Visual Studio 15
 VisualStudioVersion = 15.0.28307.779
 MinimumVisualStudioVersion = 10.0.40219.1
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Table_GridView", "6.Table_GridView\Table_GridView.csproj", "{C1BC64FE-70A5-4633-AA14-B2A05A227977}"
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Table_GridView", "Table_GridView\Table_GridView.csproj", "{C1BC64FE-70A5-4633-AA14-B2A05A227977}"
 EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution

QuickDemo/6.Table_GridView/6.Table_GridView/App.config renamed to QuickDemo/6.Table_GridView/Table_GridView/App.config

@@ -16,7 +16,7 @@ static void Main()
 		{
 			Application.EnableVisualStyles();
 			Application.SetCompatibleTextRenderingDefault(false);
-			Application.Run(new CourseSelection());
+			Application.Run(new frm_CourseSelection());
 		}
 	}
 }

QuickDemo/6.Table_GridView/6.Table_GridView/Program.cs renamed to QuickDemo/6.Table_GridView/Table_GridView/Program.cs

@@ -157,16 +157,16 @@
     <Reference Include="System.Xml" />
   </ItemGroup>
   <ItemGroup>
-    <Compile Include="CourseSelection.cs">
+    <Compile Include="frm_CourseSelection.cs">
       <SubType>Form</SubType>
     </Compile>
-    <Compile Include="CourseSelection.Designer.cs">
-      <DependentUpon>CourseSelection.cs</DependentUpon>
+    <Compile Include="frm_CourseSelection.Designer.cs">
+      <DependentUpon>frm_CourseSelection.cs</DependentUpon>
     </Compile>
     <Compile Include="Program.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
-    <EmbeddedResource Include="CourseSelection.resx">
-      <DependentUpon>CourseSelection.cs</DependentUpon>
+    <EmbeddedResource Include="frm_CourseSelection.resx">
+      <DependentUpon>frm_CourseSelection.cs</DependentUpon>
     </EmbeddedResource>
     <EmbeddedResource Include="Properties\Resources.resx">
       <Generator>ResXFileCodeGenerator</Generator>

QuickDemo/6.Table_GridView/6.Table_GridView/Properties/AssemblyInfo.cs renamed to QuickDemo/6.Table_GridView/Table_GridView/Properties/AssemblyInfo.cs

@@ -7,7 +7,7 @@ namespace GridView
     /// <summary>
     /// 选课窗体；
     /// </summary>
-    public partial class CourseSelection : Form
+    public partial class frm_CourseSelection : Form
     {
         /// <summary>
         /// 当前学号；
@@ -16,7 +16,7 @@ public partial class CourseSelection : Form
         /// <summary>
         /// 构造函数；
         /// </summary>
-        public CourseSelection()
+        public frm_CourseSelection()
         {
             InitializeComponent();
             this.LoadCourses();
@@ -28,21 +28,14 @@ private void LoadCourses()
         {
             SqlHelper sqlHelper = new SqlHelper();
             string commantText =
-                $@"SELECT C.*,'已选' AS Status 
-						FROM tb_Course AS C JOIN tb_StudentScore AS SS ON C.Number=SS.CourseNumber
-						WHERE SS.StudentNumber='{StudentNumber}'
-					UNION
-					SELECT C.*,'未选'
-						FROM tb_Course AS C
-						WHERE C.Number NOT IN
-							(SELECT SS.CourseNumber
-								FROM tb_StudentScore AS SS
-								WHERE SS.StudentNumber='{StudentNumber}');";
+                $@"SELECT C.*,IIF(SS.StudentNumber IS NULL,'未选','已选') AS Status 
+				    FROM tb_Course AS C LEFT JOIN tb_StudentScore AS SS ON C.Number=SS.CourseNumber 
+                        AND SS.StudentNumber='{StudentNumber}';";
             sqlHelper.QuickFill(commantText, this.dgv_AllCourses);
             commantText =
                 $@"SELECT C.*,IIF(SS.Score IS NULL,'可退选','不可退') AS Status 
-                        FROM tb_StudentScore AS SS JOIN tb_Course AS C ON SS.CourseNumber=C.Number 
-                        WHERE SS.StudentNumber='{StudentNumber}';";
+                    FROM tb_StudentScore AS SS JOIN tb_Course AS C ON SS.CourseNumber=C.Number 
+                    WHERE SS.StudentNumber='{StudentNumber}';";
             sqlHelper.QuickFill(commantText, this.dgv_SelectedCourses);
         }
         /// <summary>