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我正在尝试创建一些方法（GetContent 和 SaveContent）来扩展 linq2sql DataClass

显然我在滥用“this”，因为代码在 dbo.docs.InsertOnSubmit(this); 上失败了。

我的测试代码是这样的：

[TestMethod]
public void TestMethod1()
{
    var newProfile = new profile();
    newProfile.GetContent();
    newProfile.saveProfile();

}

类库是这样的：

namespace ClassLibrary1
{
    public partial class doc // extends class created by linq2sql
    {
        public int doc_ii { get; set; }    
    }
    public class profile : doc  // extends doc class with get and save
    {
        public void GetContent()
        {
            this.url = "http://";
            this.content = "<html><head>...</head>,</html>";
        }
        public void SaveProfile()
        {
            var dbo = new DataClasses1DataContext();
                                            // NullReference
            dbo.docs.InsertOnSubmit(this);  // not set to an instance of an object.
                                            //
            dbo.SubmitChanges();
        }
    }
}

异常详情

System.NullReferenceException was unhandled by user code
  HResult=-2147467261
  Message=Object reference not set to an instance of an object.
  Source=System.Data.Linq
  StackTrace:
       at System.Data.Linq.Table`1.InsertOnSubmit(TEntity entity)
       at ClassLibrary1.profile.SaveProfile() in t:\TRACKER_sln\ClassLibrary1\ClassLibrary1\profile.cs:line 26
       at UnitTestProject1.UnitTest1.TestMethod1() in t:\TRACKER_sln\ClassLibrary1\UnitTestProject1\UnitTest1.cs:line 15
  InnerException:

“下图”中的局部变量表示基类被包装为 this.base，但 dbo.docs.InsertOnSubmit(this.base); 生成“预期标识符，基数是关键字”错误

（没有足够的声誉点来发布图片）

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0 回答 0