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windows窗体应用程序怎么查询sql数据库

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悬赏园豆:200 [已解决问题] 解决于 2012-07-04 16:04
如sql有2列  一列是型号 一列是参数,怎么在自己设计的界面中输入型号,就能在界面显示出参数,目前所做的只是搭好了界面:


建好了数据库:


并连接起来了,后续应该怎么做,程序应该怎么写!!!求高手指教,急!!!!!
ggshelley的主页 ggshelley | 初学一级 | 园豆:6
提问于:2012-05-12 21:59
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最佳答案
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在”输入型号“的文本框的事件keypress双击。在这个事件中写。把这个文本框的参数赋值给sql语句:select 参数 from 表名 where 型号="你输入的型号";

把这个sql语句返回的参数赋值给winform界面的参数文本框。

private void textBox1_KeyPress(object sender, System.Windows.Forms.KeyPressEventArgs e)     

   {     

//写你的逻辑。

    }  

 

using System;
using System.Data;
using System.Data.SqlClient;

class Program
{
    static void Main()
    {
        string connectionString = GetConnectionString();
        string queryString = 
            "SELECT CategoryID, CategoryName FROM dbo.Categories;";
        using (SqlConnection connection = 
                   new SqlConnection(connectionString))
        {
            SqlCommand command = connection.CreateCommand();
            command.CommandText = queryString;

            try
            {
                connection.Open();

                SqlDataReader reader = command.ExecuteReader();

                while (reader.Read())
                {
                    Console.WriteLine("\t{0}\t{1}",
                        reader[0], reader[1]);
                }
                reader.Close();
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
            }
        }
    }

    static private string GetConnectionString()
    {
        // To avoid storing the connection string in your code, 
        // you can retrieve it from a configuration file.
        return "Data Source=(local);Initial Catalog=Northwind;"
            + "Integrated Security=SSPI";
    }
}
收获园豆:200
悟行 | 专家六级 |园豆:12240 | 2012-05-12 23:00
其他回答(5)
0

设定好对象的数据源,设置两个文本框的数据成员,把数据写到数据源中就OK。

无之无 | 园豆:5085 (大侠五级) | 2012-05-12 22:07
0

看看ado.net吧,查询数据库相信是现代开发中不可或缺的部分了.

go on coding | 园豆:343 (菜鸟二级) | 2012-05-13 00:02
0

看书,ADO.NET部分

太平洋的风 | 园豆:239 (菜鸟二级) | 2012-05-13 07:34
0

将下面代码写成一个DBHelper类

   using System;
    using System.Data;
    using System.Data.Common;
    using System.Configuration;

    public class DbHelper
    {
        private static string dbProviderName = ConfigurationManager.AppSettings["DbHelperProvider"];
        private static string dbConnectionString = ConfigurationManager.AppSettings["DbHelperConnectionString"];

        private DbConnection connection;
        public DbHelper()
        {
            this.connection = CreateConnection(DbHelper.dbConnectionString);
        }
        public DbHelper(string connectionString)
        {
            this.connection = CreateConnection(connectionString);
        }
        public static DbConnection CreateConnection()
        {
            DbProviderFactory dbfactory = DbProviderFactories.GetFactory(DbHelper.dbProviderName);
            DbConnection dbconn = dbfactory.CreateConnection();
            dbconn.ConnectionString = DbHelper.dbConnectionString;
            return dbconn;
        }
        public static DbConnection CreateConnection(string connectionString)
        {
            DbProviderFactory dbfactory = DbProviderFactories.GetFactory(DbHelper.dbProviderName);
            DbConnection dbconn = dbfactory.CreateConnection();
            dbconn.ConnectionString = connectionString;
            return dbconn;
        }

        public DbCommand GetStoredProcCommond(string storedProcedure)
        {
            DbCommand dbCommand = connection.CreateCommand();
            dbCommand.CommandText = storedProcedure;
            dbCommand.CommandType = CommandType.StoredProcedure;
            return dbCommand;
        }
        public DbCommand GetSqlStringCommond(string sqlQuery)
        {
            DbCommand dbCommand = connection.CreateCommand();
            dbCommand.CommandText = sqlQuery;
            dbCommand.CommandType = CommandType.Text;
            return dbCommand;
        }

        增加参数

        执行        

        执行事务
    }

    public class Trans : IDisposable
    {
        private DbConnection conn;
        private DbTransaction dbTrans;
        public DbConnection DbConnection
        {
            get { return this.conn; }
        }
        public DbTransaction DbTrans
        {
            get { return this.dbTrans; }
        }

        public Trans()
        {
            conn = DbHelper.CreateConnection();
            conn.Open();
            dbTrans = conn.BeginTransaction();
        }
        public Trans(string connectionString)
        {
            conn = DbHelper.CreateConnection(connectionString);
            conn.Open();
            dbTrans = conn.BeginTransaction();
        }
        public void Commit()
        {
            dbTrans.Commit();
            this.Colse();
        }

        public void RollBack()
        {
            dbTrans.Rollback();
            this.Colse();
        }

        public void Dispose()
        {
            this.Colse();
        }

        public void Colse()
        {
            if (conn.State == System.Data.ConnectionState.Open)
            {
                conn.Close();
            }
        }
    }

然后后像下面一样用即可

1)直接执行sql语句

        DbHelper db = new DbHelper();
        DbCommand cmd = db.GetSqlStringCommond("insert t1 (id)values('haha')");
        db.ExecuteNonQuery(cmd);
2)执行存储过程

        DbHelper db = new DbHelper();
        DbCommand cmd = db.GetStoredProcCommond("t1_insert");
        db.AddInParameter(cmd, "@id", DbType.String, "heihei");
        db.ExecuteNonQuery(cmd);
3)返回DataSet

        DbHelper db = new DbHelper();
        DbCommand cmd = db.GetSqlStringCommond("select * from t1");
        DataSet ds = db.ExecuteDataSet(cmd);
4)返回DataTable
        DbHelper db = new DbHelper();
        DbCommand cmd = db.GetSqlStringCommond("t1_findall");
        DataTable dt = db.ExecuteDataTable(cmd);
5)输入参数/输出参数/返回值的使用(比较重要哦)

        DbHelper db = new DbHelper();
        DbCommand cmd = db.GetStoredProcCommond("t2_insert");
        db.AddInParameter(cmd, "@timeticks", DbType.Int64, DateTime.Now.Ticks);
        db.AddOutParameter(cmd, "@outString", DbType.String, 20);
        db.AddReturnParameter(cmd, "@returnValue", DbType.Int32);

        db.ExecuteNonQuery(cmd);

        string s = db.GetParameter(cmd, "@outString").Value as string;//out parameter
        int r = Convert.ToInt32(db.GetParameter(cmd, "@returnValue").Value);//return value

6)DataReader使用

      DbHelper db = new DbHelper();
        DbCommand cmd = db.GetStoredProcCommond("t2_insert");
        db.AddInParameter(cmd, "@timeticks", DbType.Int64, DateTime.Now.Ticks);
        db.AddOutParameter(cmd, "@outString", DbType.String, 20);
        db.AddReturnParameter(cmd, "@returnValue", DbType.Int32);

        using (DbDataReader reader = db.ExecuteReader(cmd))
        {
            dt.Load(reader);
        }        
        string s = db.GetParameter(cmd, "@outString").Value as string;//out parameter
        int r = Convert.ToInt32(db.GetParameter(cmd, "@returnValue").Value);//return value


7)事务的使用.(项目中需要将基本的数据库操作组合成一个完整的业务流时,代码级的事务是必不可少的哦)
    pubic void DoBusiness()
    {
        using (Trans t = new Trans())
        {
            try
            {
                D1(t);
                throw new Exception();//如果有异常,会回滚滴
                D2(t);
                t.Commit();
            }
            catch
            {
                t.RollBack();
            }
        }
    }
    public void D1(Trans t)
    {
        DbHelper db = new DbHelper();
        DbCommand cmd = db.GetStoredProcCommond("t2_insert");
        db.AddInParameter(cmd, "@timeticks", DbType.Int64, DateTime.Now.Ticks);
        db.AddOutParameter(cmd, "@outString", DbType.String, 20);
        db.AddReturnParameter(cmd, "@returnValue", DbType.Int32);

        if (t == null) db.ExecuteNonQuery(cmd);
        else db.ExecuteNonQuery(cmd,t);

        string s = db.GetParameter(cmd, "@outString").Value as string;//out parameter
        int r = Convert.ToInt32(db.GetParameter(cmd, "@returnValue").Value);//return value
    }
    public void D2(Trans t)
    {
        DbHelper db = new DbHelper();
        DbCommand cmd = db.GetSqlStringCommond("insert t1 (id)values('..')");        
        if (t == null) db.ExecuteNonQuery(cmd);
        else db.ExecuteNonQuery(cmd, t);
    }

以上我们好像没有指定数据库连接字符串,大家如果看下DbHelper的代码,就知道要使用它必须在config中配置两个参数,如下:
    <appSettings>
        <add key="DbHelperProvider" value="System.Data.SqlClient"/>
        <add key="DbHelperConnectionString" value="Data Source=(local);Initial Catalog=DbHelperTest;Persist Security Info=True;User ID=sa;Password=sa"/>
    </appSettings>

你要做的是,就是传相关sql语句进去

az235 | 园豆:8283 (大侠五级) | 2012-05-14 08:55
0

会三层架构不?写过asp.net网站么?会的画就和网站一样!

MrCui | 园豆:162 (初学一级) | 2012-06-05 16:00
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