我正在使用 VS2010 和 SqlServer2008-r2 在 C# 中设计一个基于窗口的应用程序。我是
使用基于服务的数据库（.mdf），其中有一个包含四个字段的表，如果我存储
表中的数据并关闭应用程序并重新运行应用程序数据丢失。
为什么会这样以及如何摆脱它。
我正在使用以下例程进行保存
private void Save(object sender, EventArgs e)
{
Program.connection.Close();
bool k = srchpreventry();
try
{
if (k)
{
string query = " update orderform set Enrolment_Expected = " + textBox2.Text + ", Stock_on_Hand=" + textBox3.Text + ", Number_Required = "+ textBox4.Text + " where Name = '" + textBox1.Text + "';";
SqlCommand cmd = new SqlCommand(query, Program.connection);
cmd.ExecuteNonQuery();
Program.connection.Close();
}
else
{
// Program.connection.Open();
string query = "insert into orderform(Name,Enrolment_Expected,Stock_on_Hand,Number_Required) values('" + textBox1.Text + "', '" + textBox2.Text + "', ' " + textBox3.Text + "',' " + textBox4.Text + "')";
SqlCommand cmd = new SqlCommand(query, Program.connection);
cmd.ExecuteNonQuery();
Program.connection.Close();
}
}
catch (Exception ae)
{
string str = ae.ToString();
MessageBox.Show(str);
}
finally
{
textBox1.Text = "";
textBox2.Text = "";
textBox3.Text = "";
textBox4.Text = "";
textBox1.Enabled = false;
textBox2.Enabled = false;
textBox3.Enabled = false;
textBox4.Enabled = false;
Program.connection.Close();
}
}
public bool srchpreventry()
{
Program.connection.Open();
string query = " Select name from orderform where Name = '" + textBox1.Text + "';";
SqlCommand cmd = new SqlCommand(query, Program.connection);
SqlDataReader dtr = cmd.ExecuteReader();
if (dtr.Read() == true)
{
dtr.Close();
return true;
}
else
{
dtr.Close();
return false;
}
}
private void textBox1_TextChanged(object sender, EventArgs e)
{
Program.connection.Close();
Program.connection.Open();
string query = " Select * from orderform where Name = '" + textBox1.Text + "';";
SqlCommand cmd = new SqlCommand(query, Program.connection);
SqlDataReader dtr = cmd.ExecuteReader();
if (dtr.Read() == true)
{
textBox2.Text = dtr[1].ToString();
textBox3.Text = dtr[2].ToString();//GetString(2);
textBox4.Text = dtr[3].ToString();
}
else
{
textBox2.Text = "";
textBox3.Text = "";
textBox4.Text = "";
}
}
public static SqlConnection connection = null;
static string appath = Library_Records.Program.app_path;
string connectionstring = string.Format(@"Data Source=.\SQLEXPRESS;AttachDbFilename={0};Integrated Security=True;User Instance=True", appath);
static string dbfiles = null;
internal static string app_path
{
get { return dbfiles = "|Datadirectory|\\records.mdf"; }
}
/*******************datagrid code********************/
Program.connection.Open();
string query = "select * from orderform";
SqlDataAdapter MyDA = new SqlDataAdapter();
MyDA.SelectCommand = new SqlCommand(query, Program.connection);
DataTable table = new DataTable();
MyDA.Fill(table);
BindingSource bSource = new BindingSource();
bSource.DataSource = table;
dataGridView1.DataSource = bSource;