C# SQL更改在VS重新启动后消失
我正在学习C#和SQL交互的基础知识,我有以下表格: 它向我显示了使用VS 2013 DB builder制作的预填充DB的值,并且在上面的按钮上一切正常 这是我的桌子: 问题:C# SQL更改在VS重新启动后消失,c#,sql-server,C#,Sql Server,我正在学习C#和SQL交互的基础知识,我有以下表格: 它向我显示了使用VS 2013 DB builder制作的预填充DB的值,并且在上面的按钮上一切正常 这是我的桌子: 问题: 当我单击AddNew时,文本框被清除 接下来,填充文本框,当我单击Save时,记录显然被添加到DB(或者至少添加到DataSet?),因为它会给我一条成功消息,并在我使用上面的按钮浏览DB时显示 如果我关闭并重新打开我的应用程序(不关闭VS),我插入的记录仍然存在 但是如果我关闭并重新打开VS并再次运行我的应用程
- 当我单击AddNew时,文本框被清除李>
- 接下来,填充文本框,当我单击Save时,记录显然被添加到DB(或者至少添加到DataSet?),因为它会给我一条成功消息,并在我使用上面的按钮浏览DB时显示李>
- 如果我关闭并重新打开我的应用程序(不关闭VS)
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace SQLtest
{
/// <summary>
/// A class that constains our form
/// </summary>
public partial class Form1 : Form
{
// variables
DBconnection objConnect;
string conString;
DataSet ds;
DataRow dr;
int maxRows;
int inc = 0;
/// <summary>
/// Constructor of the class
/// </summary>
public Form1()
{
InitializeComponent();
}
/// <summary>
/// Form initialization method
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void Form1_Load(object sender, EventArgs e)
{
try
{
objConnect = new DBconnection();
conString = Properties.Settings.Default.TestConnectionString;
objConnect.connection_string = conString;
objConnect.Sql = Properties.Settings.Default.SQL;
ds = objConnect.GetConnection;
maxRows = ds.Tables[0].Rows.Count;
// MessageBox.Show("Max Rows: " + maxRows);
NavigateRecords();
}
catch (Exception err)
{
MessageBox.Show(err.Message);
}
}
// DB Navigation Methods
/// <summary>
/// Sets pointer (inc) to last row
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void btnNext_Click(object sender, EventArgs e)
{
// prevent indexOutOfBounds error
if (inc != maxRows - 1)
{
inc++;
NavigateRecords();
}
else
{
MessageBox.Show("Reached last employee. Showing the first record.");
inc = 0;
NavigateRecords();
}
}
/// <summary>
/// Sets pointer (inc) to previous row (if possible)
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void btnPrevious_Click(object sender, EventArgs e)
{
// prevent indexOutOfBounds error
if (inc != 0)
{
inc--;
NavigateRecords();
}
else
{
MessageBox.Show("Reached first employee. Showing the last record.");
inc = maxRows - 1;
NavigateRecords();
}
}
/// <summary>
/// Sets pointer (inc) to first row
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void btnFirst_Click(object sender, EventArgs e)
{
if (inc != 0)
{
inc = 0;
NavigateRecords();
}
else
{
MessageBox.Show("Already on first employee.");
}
}
/// <summary>
/// Sets pointer (inc) to last row
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void btnLast_Click(object sender, EventArgs e)
{
if (inc != maxRows - 1)
{
inc = maxRows - 1;
NavigateRecords();
}
else
{
MessageBox.Show("Already on last employee.");
}
}
/// <summary>
/// Main Navigation Method
/// </summary>
private void NavigateRecords()
{
dr = ds.Tables[0].Rows[inc];
txtFirstName.Text = dr.ItemArray.GetValue(1).ToString();
txtLastName.Text = dr.ItemArray.GetValue(2).ToString();
txtJobTitle.Text = dr.ItemArray.GetValue(3).ToString();
txtDepartment.Text = dr.ItemArray.GetValue(4).ToString();
}
/// <summary>
/// Exit button handler
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void btnExit_Click(object sender, EventArgs e)
{
Application.Exit();
}
/// <summary>
/// Add new record Button. Simply clears text fields, ready for a new record to be added.
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void btnAddNew_Click(object sender, EventArgs e)
{
txtFirstName.Clear();
txtLastName.Clear();
txtJobTitle.Clear();
txtDepartment.Clear();
btnAddNew.Enabled = false;
btnSave.Enabled = true;
btnCancel.Enabled = true;
}
/// <summary>
/// Save a new record button
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void btnSave_Click(object sender, EventArgs e)
{
DataRow newRow = ds.Tables[0].NewRow();
// newRow[0] is the id, thus its filled automatically
newRow[1] = txtFirstName.Text;
newRow[2] = txtLastName.Text;
newRow[3] = txtJobTitle.Text;
newRow[4] = txtDepartment.Text;
ds.Tables[0].Rows.Add(newRow);
try
{
objConnect.UpdateDB(ds);
maxRows++;
inc = maxRows - 1;
MessageBox.Show("DB updated successfully");
}
catch (Exception err)
{
MessageBox.Show(err.Message);
}
btnAddNew.Enabled = true;
btnSave.Enabled = false;
btnCancel.Enabled = false;
}
/// <summary>
/// Cancel new record button. Simply call NavigateRecords() method, and restores buttons.
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void btnCancel_Click(object sender, EventArgs e)
{
NavigateRecords();
btnAddNew.Enabled = true;
btnSave.Enabled = false;
btnCancel.Enabled = false;
}
}
}
使用系统;
使用System.Collections.Generic;
使用系统组件模型;
使用系统数据;
使用系统图;
使用System.Linq;
使用系统文本;
使用System.Threading.Tasks;
使用System.Windows.Forms;
名称空间SQLtest
{
///
///保持我们的状态的班级
///
公共部分类Form1:Form
{
//变数
数据库连接对象连接;
串构造;
数据集ds;
数据行dr;
int最大行;
int inc=0;
///
///类的构造函数
///
公共表格1()
{
初始化组件();
}
///
///表单初始化方法
///
///
///
私有void Form1\u加载(对象发送方、事件参数e)
{
尝试
{
objConnect=new DBconnection();
consting=Properties.Settings.Default.TestConnectionString;
objConnect.connection_string=构造;
objConnect.Sql=Properties.Settings.Default.Sql;
ds=objConnect.GetConnection;
maxRows=ds.Tables[0].Rows.Count;
//MessageBox.Show(“最大行数:”+maxRows);
导航记录();
}
捕获(异常错误)
{
MessageBox.Show(错误消息);
}
}
//数据库导航方法
///
///将指针(inc)设置为最后一行
///
///
///
private void btnNext_单击(对象发送方,事件参数e)
{
//防止索引自动边界错误
如果(inc!=maxRows-1)
{
inc++;
导航记录();
}
其他的
{
Show(“到达最后一名员工。显示第一条记录”);
inc=0;
导航记录();
}
}
///
///将指针(inc)设置为上一行(如果可能)
///
///
///
private void btnPrevious_Click(对象发送者,事件参数e)
{
//防止索引自动边界错误
如果(inc!=0)
{
公司--;
导航记录();
}
其他的
{
Show(“到达第一个员工。显示最后一条记录”);
inc=最大行数-1;
导航记录();
}
}
///
///将指针(inc)设置为第一行
///
///
///
私有void btnFirst_单击(对象发送方,事件参数e)
{
如果(inc!=0)
{
inc=0;
导航记录();
}
其他的
{
MessageBox.Show(“已在第一个员工身上”);
}
}
///
///将指针(inc)设置为最后一行
///
///
///
私有无效btnLast_单击(对象发送方,事件参数e)
{
如果(inc!=maxRows-1)
{
inc=最大行数-1;
导航记录();
}
其他的
{
MessageBox.Show(“已在上一个员工身上”);
}
}
///
///主导航方法
///
专用void导航记录()
{
dr=ds.表[0].行[inc];
txtFirstName.Text=dr.ItemArray.GetValue(1.ToString();
txtLastName.Text=dr.ItemArray.GetValue(2.ToString();
txtJobTitle.Text=dr.ItemArray.GetValue(3.ToString();
txtDepartment.Text=dr.ItemArray.GetValue(4.ToString();
}
///
///退出按钮处理程序
///
///
///
私有void btnExit\u单击(对象发送者,事件参数e)
{
Application.Exit();
}
///
///添加新记录按钮。只需清除文本字段,即可添加新记录。
///
///
///
私有无效btnAddNew_单击(对象发送者,事件参数e)
{
txtFirstName.Clear();
txtLastName.Clear();
txtJobTitle.Clear();
txtDepartment.Clear();
btnAddNew.Enabled=false;
btnSave.Enabled=true;
btnCancel.Enabled=真;
}
///
///保存新记录按钮
///
///
///
私有void btnSave\u单击(对象发送方,事件参数e)
{
DataRow newRow=ds.Tables[0].newRow();
//newRow[0]是id,因此它会自动填充
newRow[1]=txtFirstName.Text;
newRow[2]=txtLastName.Text;
newRow[3]=txtJobTitle.Text;
newRow[4]=txtDepartment.Text;
ds.Tables[0].Rows.Add(newRow);
尝试
{
objConnect.UpdateDB(ds);
maxRows++;
inc=最大行数-1;
MessageBox.Show(“数据库更新成功”);
}
捕获(异常错误)
{
MessageBox.Show(错误消息);
}
btnAddNew.Enabled=true;
btnSave.Enabled=false;
btnCancel.Enabled=false;
}
///
///取消新记录按钮。只需调用NavigateRecords()方法并还原按钮。
///
///
///
私有void btnCancel\u单击(对象发送者,事件参数e)
{
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace SQLtest
{
/// <summary>
/// A class that makes the connection to the SQL Database
/// </summary>
class DBconnection
{
// variables
private string sql_string;
private string strCon;
System.Data.SqlClient.SqlDataAdapter da_1;
// set methods
public string Sql
{
set { sql_string = value; }
}
public string connection_string
{
set { strCon = value; }
}
// DataSet
public System.Data.DataSet GetConnection
{
get { return MyDataSet(); }
}
// MyDataSet method
private System.Data.DataSet MyDataSet()
{
System.Data.SqlClient.SqlConnection con = new System.Data.SqlClient.SqlConnection(strCon);
con.Open();
da_1 = new System.Data.SqlClient.SqlDataAdapter(sql_string, con);
System.Data.DataSet dat_set = new System.Data.DataSet();
da_1.Fill(dat_set,"Table_Data_1");
con.Close();
return dat_set;
}
// Update DB method
public void UpdateDB(System.Data.DataSet ds)
{
System.Data.SqlClient.SqlCommandBuilder cb = new System.Data.SqlClient.SqlCommandBuilder(da_1);
cb.DataAdapter.Update(ds.Tables[0]);
}
}
}