C# LINQ to SQL 对象名称无效

Posted 2023-03-30

【中文标题】C# LINQ to SQL 对象名称无效

【英文标题】：C# LINQ to SQL Invalid Object Name

【发布时间】：2016-07-01 18:48:48

【问题描述】：

public class AMCOMDB : DataContext

        public Table<student> allStudents;
        public Table<aClass> allClasses;
        public AMCOMDB(string connection) : base(connection)   


[Table(Name = "student")]
public class student

        private string _studentName;

        [Column(IsPrimaryKey =true,Storage ="_studentName")]
        public string studentName
        
            get  return this._studentName; 
            set  this._studentName = value; 
        

        private string _LARType;

        [Column(Storage ="_LARType")]
        public string LARType
        
            get  return this._LARType; 
            set  this._LARType = value; 
        

        private string _studentType;

        [Column(Storage = "_studentType")]
        public string studentType
        
            get  return this._studentType; 
            set  this._studentType = value; 
        

        private string _aviationLevel;

        [Column(Storage = "_aviationLevel")]
        public string aviationLevel
        
            get  return this._aviationLevel;  
            set  this._aviationLevel = value; 
        
        private string _airDefenseLevel;
        [Column(Storage = "_airDefenseLevel")]
        public string airDefenseLevel
        
            get
            
                return this._airDefenseLevel;
            
            set
            
                this._airDefenseLevel = value;
            
        
        private string _emergencyContact;
        [Column(Storage = "_emergencyContact")]
        public string emergencyContact
        
            get
            
                return this._emergencyContact;
            
            set
            
                this._emergencyContact = value;
            
        
[Table(Name = "grades")]
    public class grades
    
        private string _studentName;
        [Column(IsPrimaryKey = true, Storage = "_studentName")]
        public string studentName
        
            get
            
                return this._studentName;
            
            set
            
                this._studentName = value;
            
        
        private int _ET;
        [Column(Storage = "_ET")]
        public int ET
        
            get
            
                return this._ET;
            
            set
            
                this._ET = value;
            
        
        private int _CP;
        [Column(Storage = "_CP")]
        public int CP
        
            get
            
                return this._CP;
            
            set
            
                this._CP = value;
            
        
        private int _SB;
        [Column(Storage = "_SB")]
        public int SB
        
            get
            
                return this._SB;
            
            set
            
                this._SB = value;
            
        
        private int _EC;
        [Column(Storage = "_EC")]
        public int EC
        
            get
            
                return this._EC;
            
            set
            
                this._EC = value;
            
        
        private int _finalGrade;
        [Column(Storage = "_finalGrade")]
        public int finalGrade
        
            get
            
                return this._finalGrade;
            
            set
            
                this._finalGrade = value;
            
        
       
[Table(Name = "classes")]
    public class aClass
    
        private string _classNumber;
        [Column(IsPrimaryKey = true, Storage = "_classNumber")]
        public string classNumber
        
            get
            
                return this._classNumber;
            
            set
            
                this._classNumber = value;
            
        
        private string _courseSeries;
        [Column(Storage = "_courseSeries")]
        public string courseSeries
        
            get
            
                return this._courseSeries;
            
            set
            
                this._courseSeries = value;
            
        
        private string _courseNumber;
        [Column(Storage = "_courseNumber")]
        public string courseNumber
        
            get
            
                return this._courseNumber;
            
            set
            
                this._courseNumber = value;
            
        
        private string _distanceLearning;
        [Column(Storage = "_distanceLearning")]
        public string distanceLearning
        
            get
            
                return this._distanceLearning;
            
            set
            
                this._distanceLearning = value;
            
        
        private string _classStartDate;
        [Column(Storage = "_classStartDate")]
        public string classStartDate
        
            get
            
                return this._classStartDate;
            
            set
            
                this._classStartDate = value;
            
        
        private string _classEndDate;
        [Column(Storage = "_classEndDate")]
        public string classEndDate
        
            get
            
                return this._classEndDate;
            
            set
            
                this._classEndDate = value;
            
        
        private string _primaryInstructor;
        [Column(Storage = "_primaryInstructor")]
        public string primaryInstructor
        
            get
            
                return this._primaryInstructor;
            
            set
            
                this._primaryInstructor = value;
            
        
        private string _secondaryInstructor;
        [Column(Storage = "_secondaryInstructor")]
        public string secondaryInstructor
        
            get
            
                return this._secondaryInstructor;
            
            set
            
                this._secondaryInstructor = value;
            
        
        private string _location;
        [Column(Storage = "_location")]
        public string location
        
            get
            
                return this._location;
            
            set
            
                this._location = value;
            
        
        private string _TDYCosts;
        [Column(Storage = "_TDYCosts")]
        public string TDYCosts
        
            get
            
                return this._TDYCosts;
            
            set
            
                this._TDYCosts = value;
            
        
        private string _studentCount;
        [Column(Storage = "_studentCount")]
        public string studentCount
        
            get
            
                return this._studentCount;
            
            set
            
                this._studentCount = value;
            
        
        private List<grades> _classGrades;
        [Column(Storage = "_classGrades")]
        public List<grades> classGrades
        
            get
            
                return this._classGrades;
            
            set
            
                this._classGrades = value;
            
        
AMCOMDB ADB = new AMCOMDB(connectionString);
        if (ADB.DatabaseExists())
        

            var stud = ADB.GetTable<student>();
            var clas = ADB.GetTable<aClass>();
            IQueryable<string> query = from c in stud
                                       where c.studentName.Length > 5
                                       orderby c.studentName.Length
                                       select c.studentName.ToUpper();
            foreach (string name in query)
            

            
            //var q = from a in ADB.GetTable<student>()
            //       select a;
            //dtStudents = LinqQuerytoDataTable(q);
            //var q1 = from a in ADB.GetTable<aClass>()
            //         select a;
            //aClass c = new aClass();

            //dtClasses = reformatDataTable(q1);
        

当我尝试在 (foreach (查询中的字符串名称)) 处从数据库中获取信息时，我收到以下信息

System.Data.dll 中出现“System.Data.SqlClient.SqlException”类型的未处理异常

附加信息：无效的对象名称“学生”。

我在第一次创建数据库时也得到了这个：

System.Data.Linq.dll 中出现“System.InvalidOperationException”类型的未处理异常

附加信息：无法确定“System.Collections.Generic.List`1[WindowsFormsApplication1.Form1+grades]”的 SQL 类型。

【问题讨论】：

范围太广，无法回答。至少指出哪一行给你错误，

foreach（查询中的字符串名称）行给出：System.Data.dll 中发生“System.Data.SqlClient.SqlException”类型的未处理异常附加信息：无效的对象名称“学生” '。

请将上述信息添加到问题中，以便读者不必通读 cmets 以获得足够的信息来提供帮助。谢谢！

要么没有连接到正确的数据库，要么没有足够的权限读取student。

@Marrion 你能告诉我们 Cotntext 的 GetTable 方法吗？您是否尝试通过 var stud = ADB.allStudents 直接访问 allStudents 以隔离表 student 是否实际存在于您尝试连接的数据库中的问题？

【参考方案1】：

删除对我有用的名称一词

[Table("student")]
public class student