form1.cs

java基础方面的一些实例代码

			{
				MessageBox.Show("目前没有连接任何数据库");
			}
		}

		private void DisConn_Click(object sender, System.EventArgs e)
		{
			try 
			{
				MyOleConn.Close( );
				MyOleConn.Dispose( );
				bIsConnected = false;
			}
			catch 
			{
			}
		}

		private void XmlBuild_Click(object sender, System.EventArgs e)
		{
			//在当前目录的Debug下将本数据库写成MyXmlDBDesciption.xml文件
			MyDataSet.WriteXml("MyXmlDBDesciption.xml");

			//然后将所写的MyXmlDBDesciption.xml文件显示在MessageBox中以证明成功书写
			string XmlStr = MyDataSet.GetXml();
			MessageBox.Show(XmlStr);

			//最后从所写的MyXmlDBDesciption.xml文件中读取数据库内容恢复程数据库表读取到
			//的表另外存于新建的DataSet对象MyXmlDataSet中，并作为数据源在DataGrid控件
			//中显示，另外创建DataSet对象，目的是说明重新读取而不是原来已经读到的数据
			DataSet MyXmlDataSet = new DataSet();
			MyXmlDataSet.ReadXml("MyXmlDBDesciption.xml");
			dataGrid1.SetDataBinding(MyXmlDataSet, "teacherinfo");
		}

		private void MulQuery_SelectedIndexChanged(object sender, System.EventArgs e)
		{
			int CurrentIndex = MulQuery.SelectedIndex;
				
			if (bIsConnected == false) 
			{
				MessageBox.Show("目前没有连接任何数据库或者没有读取数据库数据");
				return;
			}
			MulTableQuery(CurrentIndex+1);
		}

		private void MulTableQuery(int index)
		{
			int i = 0;
			string [] CourseStr = {"","","","","",""};	
			DataTable CurrentTable = MyDataSet.Tables[0];
			string SQLStr = "";
			//string SQLStr = "SELECT * FROM teacherinfo";
	//		MyDataAdapter.SelectCommand = new OleDbCommand(SQLStr,MyOleConn);
			DataView myView;
			string TIDStr = "";
			switch (index) 
			{
				case 1:
					myView = new DataView(CurrentTable,"PostTitle = '教授'", 				
							"PostTitle", DataViewRowState.CurrentRows);
					foreach (DataRowView myDrv in myView)
					{
						TIDStr = myDrv[0].ToString();
						CurrentTable = MyDataSet.Tables[3];
						DataView myView1 = new DataView(CurrentTable, "TID = "+"'"+TIDStr+"'", 
							"TID", DataViewRowState.CurrentRows);
						SQLStr = TIDStr + "号 " +myDrv[3].ToString()+myDrv[2].ToString();
						foreach (DataRowView myDrv1 in myView1)
						{					
							SQLStr = SQLStr + myDrv1[2] + " " + myDrv1[3] + " " + myDrv1[4] + " " + myDrv1[5];
							CourseStr[i++] = SQLStr;
						}
					}
					listBox3.DataSource = CourseStr;
				break;
				case 2:
					/*myView = new DataView(CurrentTable,"PostTitle = '副教授'", 				
						"PostTitle", DataViewRowState.CurrentRows);
					foreach (DataRowView myDrv in myView)
					{
						TIDStr = myDrv[0].ToString();
						CurrentTable = MyDataSet.Tables[3];
						DataView myView1 = new DataView(CurrentTable, "TID = "+"'"+TIDStr+"'", 
							"TID", DataViewRowState.CurrentRows);
						SQLStr = TIDStr + "号 " +myDrv[3].ToString()+myDrv[2].ToString();
						foreach (DataRowView myDrv1 in myView1)
						{					
							SQLStr = SQLStr + myDrv1[2] + " " + myDrv1[3] + " " + myDrv1[4] + " " + myDrv1[5];
							CourseStr[i++] = SQLStr;
						}
					}
					listBox3.DataSource = CourseStr;*/
				/*	SQLStr = "SELECT TID, LastName FROM teacherinfo Where PostTitle = '副教授'";
					DataRow [] foundRow = CurrentTable.Select(SQLStr);
					foreach (DataRow myRow in foundRow)						
					{
						TIDStr = myRow[1].ToString();
						SQLStr = TIDStr + "号 " +myRow[3].ToString()+myRow[2].ToString()+" ";
						DataRow [] foundRow1 = MyDataSet.Tables["teacherclass"].Select( "SELECT FROM teacherclass WHERE ITD = myRow[1]");
						foreach (DataRow myRow1 in foundRow1)
						{
							SQLStr = SQLStr + myRow1[2] + " " + myRow1[3] + " " +myRow1[4] + " " + myRow1[5];
							CourseStr[i++] = SQLStr;
						}
					}
					listBox3.DataSource = CourseStr;*/
				break;
		//		case 1:
		//		break;
			}				
					
			
			//DataRow [] foundrows = CurrentTable.Select(SQLStr);
			/*DataRelation ProfessorCourseRel = MyDataSet.Relations.Add("ProfessorCourse",
					MyDataSet.Tables[0].Columns["TID"], MyDataSet.Tables[3].Columns["TID"]);*/

		}

		private void DeleteB_Click(object sender, System.EventArgs e)
		{
			CurrentModifyTable = (DataTable)dataGrid1.DataSource;
	//		int i = dataGrid1.CurrentCell.RowNumber;
	//		CurrentTable.Rows[i].Delete( );
			CurrentModifyTable.Rows[0].Delete( );  //删除第一条记录		
			ModifyB.Enabled = false;
		}

		private void ReceiveB_Click(object sender, System.EventArgs e)
		{
			try 
			{
				CurrentModifyTable.AcceptChanges( );
			}
			catch 
			{
			}
		}

		private void RejectB_Click(object sender, System.EventArgs e)
		{
			try 
			{
				CurrentModifyTable.RejectChanges( );
			} 
			catch 
			{
			}
		}

		private void ModifyB_Click(object sender, System.EventArgs e)
		{
			CurrentModifyTable = MyDataSet.Tables[0];
			DataRow myDataRow = CurrentModifyTable.Rows[0];
			myDataRow.BeginEdit();
			myDataRow[6] = "没有职称";
			myDataRow.EndEdit();
		//	MyDataSet.Tables[0].AcceptChanges( );
		//	MyDataAdapter.Update(MyDataSet, "teacherinfo");
		//	dataGrid1.SetDataBinding(MyDataSet.Tables[0], null);
		}

		private void InsertB_Click(object sender, System.EventArgs e)
		{
			//首先设置主键，用于查询所要添加的行是否已经存在
			DataColumn [] keys = new DataColumn[2];
			keys[0] = MyDataSet.Tables[0].Columns["TID"];
			MyDataSet.Tables[0].PrimaryKey = keys;
			DataRow findRow = MyDataSet.Tables[0].Rows.Find(10);
			if (findRow != null) 
			{
				MessageBox.Show("要添加的工号为10的教师已经存在");
				return;
			}

			//如果不存在，然后添加
			CurrentModifyTable = MyDataSet.Tables[0];
			DataRow addRow = MyDataSet.Tables[0].NewRow( );
			addRow[1] = 10;	addRow[2] = "电";	addRow[3] = "赵";
			addRow[4] = 202;addRow[5] = 124356;	addRow[6] = "讲师";
			MyDataSet.Tables[0].Rows.Add( addRow );
		}

		private void ResultB_Click(object sender, System.EventArgs e)
		{
			MessageBox.Show(CurrentModifyTable.ToString());
			MyDataAdapter.Update(MyDataSet, CurrentModifyTable.ToString());
		}

		private void NewTable_Click(object sender, System.EventArgs e)
		{
			//build new table
			string StrTemp = "";
		/*	try 
			{
				OleDbDataAdapter MyStudentAdapter = new OleDbDataAdapter(
					"SELECT SID,Name, FROM studentinfo",MyOleConn);
				OleDbCommandBuilder builder = new OleDbCommandBuilder(MyStudentAdapter);
				DataRelation [] studentcourseRel = new DataRelation[5];
				studentcourseRel[0] = MyDataSet.Relations.Add("classinfo",
					MyDataSet.Tables["classinfo"].Columns["Class1"],
					MyDataSet.Tables["studentinfo"].Columns["CNO"]);
				studentcourseRel[1] = MyDataSet.Relations.Add("classinfo",
					MyDataSet.Tables["classinfo"].Columns["CNO"],
					MyDataSet.Tables["studentinfo"].Columns["Class2"]);
				studentcourseRel[2] = MyDataSet.Relations.Add("classinfo",
					MyDataSet.Tables["classinfo"].Columns["CNO"],
					MyDataSet.Tables["studentinfo"].Columns["Class3"]);
				studentcourseRel[3] = MyDataSet.Relations.Add("classinfo",
					MyDataSet.Tables["classinfo"].Columns["CNO"],
					MyDataSet.Tables["studentinfo"].Columns["Class4"]);
				studentcourseRel[4] = MyDataSet.Relations.Add("classinfo",
					MyDataSet.Tables["classinfo"].Columns["CNO"],
					MyDataSet.Tables["studentinfo"].Columns["Class5"]);

				foreach(DataRow courseRow in MyDataSet.Tables["classinfo"].Rows)
				{
					StrTemp = "CourseNo:" + courseRow["CNO"]+"Course:"+courseRow["CName"]+"\n";
					
					for (int i = 0; i< 5; i++) 
					{
						foreach(DataRow studentRow in courseRow.GetChildRows(studentcourseRel[i]))
							StrTemp = StrTemp + "student name:" + studentRow["SNane"];
											
					}
	
				}
				MessageBox.Show(StrTemp);
			}
			catch
			{
				MessageBox.Show("Wrong");
			}*/
		}
		
		private void button1_Click(object sender, System.EventArgs e)
		{
			//将第一个表的每个字段的属性列出来
			dataGrid1.SetDataBinding(MyDataTable[0], null);

			//通过执行命令创建一个暂时的表
			try 
			{
				MyOleConn.Close();
				OleDbCommand nonqueryCommand = MyOleConn.CreateCommand();
				MyOleConn.Open();
				nonqueryCommand.CommandText = 
					"CREATE TABLE MyNewTable(Name VARCHAR(30),TestNumber integer, Title VARCHAR(30))";
				nonqueryCommand.ExecuteNonQuery();
				// create INSERT command with named parameters
				nonqueryCommand.CommandText = 
					"INSERT INTO MyNewTable VALUES (@Name, @Number, @Title)" ;

				// add parameters to Command object Parameters collection
				nonqueryCommand.Parameters.Add("@Name", OleDbType.VarChar, 30);
				nonqueryCommand.Parameters.Add("@Number", OleDbType.Integer);
				nonqueryCommand.Parameters.Add("@Title", OleDbType.VarChar, 30);
				
				// prepare INSERT command for repeated execution
				nonqueryCommand.Prepare();
				
				// data to be inserted
				string[] names = { "Enrico", "Franco", "Gloria", "Horace" } ;
				string[] titles = { "女", "男", "男", "女" } ;
				int i;
				for (i=1; i<=4; i++)
				{
					nonqueryCommand.Parameters["@Name"].Value = names[i-1];
					nonqueryCommand.Parameters["@Number"].Value = i;
					nonqueryCommand.Parameters["@Title"].Value = titles[i-1];				
				}	
			}
			catch (OleDbException ex) 
			{
				MessageBox.Show(ex.ToString());
			}
		}

		private void DataReaderB_Click(object sender, System.EventArgs e)
		{
			string TableStr = "";
			try
			{
				MyComm = new OleDbCommand("SELECT * FROM teacherinfo",MyOleConn);
				MyDataReader.Close();
				MyDataReader = MyComm.ExecuteReader(); 
				while (MyDataReader.Read()) 
				{
					TableStr = TableStr+MyDataReader[1]+" "+MyDataReader[3]+MyDataReader[2]+ " " 
						+MyDataReader[6]+"\n";
				}
				MessageBox.Show(TableStr);
			}
			catch
			{
				MessageBox.Show("目前没有连接任何数据库或者没有读取数据库数据");
			}
		}

	}
}