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!!!!!
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"; } }
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。
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.
看书,ADO.NET部分
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
会三层架构不?写过asp.net网站么?会的画就和网站一样!