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mysqlデータベースからデータを取得するためにC＃コードのセグメントを作成しています。私は既製の例から始めましたが、それは私にエラーを与えましたrdr = cmd.ExecuteReader()

スローされた例外のスクリーンショットも以下に示されています

例外がスローされたスクリーンショット 

using System;
using MySql.Data.MySqlClient; 

public class Program
{

    static void Main() 
    {
            string serverName = "192.168.0.012";
            string port = "1234";
            string db = "cust_db";
            string userID = "root";
            string password = "pass";
            string cs = "Server=" + serverName + ";Port=" + port + ";Database=" + db + ";Uid=" + userID + ";password=" + password;


        MySqlConnection conn = null;
        MySqlDataReader rdr = null;

        try 
        {
            conn = new MySqlConnection(cs);
            conn.Open();

            string stm = "SELECT * FROM cust_tb";
            MySqlCommand cmd = new MySqlCommand(stm, conn);
            rdr = cmd.ExecuteReader();

            while (rdr.Read()) 
            {
                Console.WriteLine(rdr.GetInt32(0) + ": " 
                    + rdr.GetString(1));
            }

        } catch (MySqlException ex) 
        {
            Console.WriteLine("Error: {0}",  ex.ToString());

        } finally 
        {
            if (rdr != null) 
            {
                rdr.Close();
            }

            if (conn != null) 
            {
                conn.Close();
            }

        }
    }
}


at MySql.Data.MySqlClient.CharSetMap.GetChararcterSet(DBVersion version, String CharSetName)
   at MySql.Data.MySqlClient.NativeDriver.GetFieldMetaData41()
   at MySql.Data.MySqlClient.NativeDriver.GetFieldMetaData()
   at MySql.Data.MySqlClient.NativeDriver.ReadColumnMetadata(Int32 count)
   at MySql.Data.MySqlClient.MySqlDataReader.NextResult()
   at MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior)
   at MySql.Data.MySqlClient.MySqlCommand.ExecuteReader()
   at Program.Main() in c:\Users\omran.alhammadi\Desktop\csMysqlConnection\csMysqlConnection\Program.cs:line 28
   at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
   at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
   at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
   at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
   at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Threading.ThreadHelper.ThreadStart()</StackTrace><ExceptionString>System.Collections.Generic.KeyNotFoundException: The given key was not present in the dictionary.
   at System.Collections.Generic.Dictionary`2.get_Item(TKey key)
   at MySql.Data.MySqlClient.CharSetMap.GetChararcterSet(DBVersion version, String CharSetName)
   at MySql.Data.MySqlClient.NativeDriver.GetFieldMetaData41()
   at MySql.Data.MySqlClient.NativeDriver.GetFieldMetaData()
   at MySql.Data.MySqlClient.NativeDriver.ReadColumnMetadata(Int32 count)
   at MySql.Data.MySqlClient.MySqlDataReader.NextResult()
   at MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior)
   at MySql.Data.MySqlClient.MySqlCommand.ExecuteReader()
   at Program.Main() in c:\Users\omran.alhammadi\Desktop\csMysqlConnection\csMysqlConnection\Program.cs:line 28
   at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
   at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
   at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
   at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
   at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Threading.ThreadHelper.ThreadStart()</ExceptionString></Exception></TraceRecord>
An unhandled exception of type 'System.Collections.Generic.KeyNotFoundException' occurred in mscorlib.dll
Additional information: The given key was not present in the dictionary.
The program '[17084] csMysqlConnection.vshost.exe: Managed (v4.0.30319)' has exited with code -1 (0xffffffff).
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1 に答える 1

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私はこの問題を抱えていて、いくつかの調査を行いました。しばらくして、私はこの問題を修正しました。

私の問題はデータベーステーブルのエンコーディングでした。持っていたutf32_unicode_ciので、に変更しましたutf8_unicode_ci。今では完璧に動作します。

幸運を祈っています。

于 2013-03-06T00:37:19.840 に答える