如何将类项添加到数据库 [英] How do I add a class item to a database

问题描述

如何将类项添加到数据库？



我在classlist [n] .col1中的@ col1中收到错误。

  public   class  Class1 
 {
  public   Int32  id { get < /跨度>;  set ; } 
  public   string  col1 { get ;  set ; } 
  public   string  col2 { get ;  set ; } 
  public   string  col3 { get ;  set ; } 
} 
 

列表< Class1> classlist =  new  List< Class1>（）; 
 classlist.Add（ new  Class1（）{id =  1 ，col1 =   11，col2 =   22，col3 =   33}）; 
 classlist.Add（ new  Class1（）{id =  2 ，col1 =   44，col2 =   55，col3 =   66}）; 
 classlist.Add（ new  Class1（）{id =  3 ，col1 =   77，col2 =   88，col3 =   99}）; 
  string  connStr = ConfigurationManager.ConnectionStrings [  MDFdb]的ConnectionString。 
  string  cmdStr =   INSERT INTO [Table1 ]（col1，col2，col3）VALUES（@ col1，@ col2，@ col3）;; 
  for （ int  n =  1 ; n <  = classlist.Count; n ++）
 {
  try  
 {
 使用（SqlConnection conn =  new  SqlConnection（connStr））
 {
 使用（SqlCommand cmd =  new  SqlCommand（cmdStr，conn））
 {
 conn.Open（）; 
 cmd.ExecuteNonQuery（）; 
 cmd.Parameters.Add（  @ col1，classlist [n] .col1） ; 
 cmd.Parameters.Add（  @ col2，classlist [n] .col2） ; 
 cmd.Parameters.Add（  @ col3，classlist [n] .col3） ; 
 conn.Close（）; 
 conn.Dispose（）; 
} 
} 
} 
  catch （例外情况）
 {
 Label1.Text = ex.ToString（）; 
} 
} 
 

错误代码：

 System.Data.SqlClient.SqlException（0x80131904）：必须声明标量变量@ col1。在System.Data.SqlClient.SqlClient上的System.Data.SqlClient.SqlConnection.OnError（SqlException异常，Boolean breakConnection，Action`1 wrapCloseInAction）处于System.Data.SqlClient.SqlInternalConnection.OnError（SqlException异常，Boolean breakConnection，Action`1 wrapCloseInAction） System.Data.SqlClient上的System.Data.SqlClient.TdsParser.TryRun（RunBehavior runBehavior，SqlCommand cmdHandler，SqlDataReader dataStream，BulkCopySimpleResultSet bulkCopyHandler，TdsParserStateObject stateObj，Boolean& dataReady）中的.TdsParser.ThrowExceptionAndWarning（TdsParserStateObject stateObj，Boolean callerHasConnectionLock，Boolean asyncClose） System.Data上的System.Data.SqlClient.SqlCommand.InternalExecuteNonQuery（TaskCompletionSource`1完成，String methodName，Boolean sendToPipe，Int32 timeout，Boolean asyncWrite）中的.SqlCommand.RunExecuteNonQueryTds（String methodName，Boolean async，Int32 timeout，Boolean asyncWrite）。 ClassToMDF._Default.Button1_Click（O中的SqlClient.SqlCommand.ExecuteNonQuery（） bject sender，EventArgs e）in C：\Users\User\path \Default.aspx.cs：第36行ClientConnectionId：e373b91f-0471-4487-9667-bed0597b6391 

解决方案

尝试将类序列化为xml或Json字符串并将其保存到数据库中。



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How do I add a class item to a database?

I am getting an error in "@col1" in "classlist[n].col1".

public class Class1
{
    public Int32 id { get; set; }
    public string col1 { get; set; }
    public string col2 { get; set; }
    public string col3 { get; set; }
}

List<Class1> classlist = new List<Class1>();
classlist.Add(new Class1() { id = 1, col1 = "11", col2 = "22", col3="33" });
classlist.Add(new Class1() { id = 2,  col1 = "44", col2 = "55", col3="66" });
classlist.Add(new Class1() { id = 3,  col1 = "77", col2 = "88", col3="99" });
string connStr = ConfigurationManager.ConnectionStrings["MDFdb"].ConnectionString;
string cmdStr = "INSERT INTO [Table1] (col1,col2,col3) VALUES (@col1,@col2,@col3);";
for (int n = 1; n <= classlist.Count; n++)
{
    try
    {
        using (SqlConnection conn = new SqlConnection(connStr))
        {
            using (SqlCommand cmd = new SqlCommand(cmdStr, conn))
            {
                conn.Open();
                cmd.ExecuteNonQuery();
                cmd.Parameters.Add("@col1", classlist[n].col1);
                cmd.Parameters.Add("@col2", classlist[n].col2);
                cmd.Parameters.Add("@col3", classlist[n].col3);
                conn.Close();
                conn.Dispose();
            }
        }
    }
    catch (Exception ex)
    {
        Label1.Text=ex.ToString();
    }
}

Error Code:

System.Data.SqlClient.SqlException (0x80131904): Must declare the scalar variable "@col1". at System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection, Action`1 wrapCloseInAction) at System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection, Action`1 wrapCloseInAction) at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj, Boolean callerHasConnectionLock, Boolean asyncClose) at System.Data.SqlClient.TdsParser.TryRun(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj, Boolean& dataReady) at System.Data.SqlClient.SqlCommand.RunExecuteNonQueryTds(String methodName, Boolean async, Int32 timeout, Boolean asyncWrite) at System.Data.SqlClient.SqlCommand.InternalExecuteNonQuery(TaskCompletionSource`1 completion, String methodName, Boolean sendToPipe, Int32 timeout, Boolean asyncWrite) at System.Data.SqlClient.SqlCommand.ExecuteNonQuery() at ClassToMDF._Default.Button1_Click(Object sender, EventArgs e) in C:\Users\User\path\Default.aspx.cs:line 36 ClientConnectionId:e373b91f-0471-4487-9667-bed0597b6391 

解决方案

Try serializing the class into a xml or Json String and save that to your Database.

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