连接到 Access 数据库

Question

I'm trying to connect to database file "crepeDB.accdb"

When I added it through data connection, and works fine when I drag any table to appear as data grid in any form but when I try to connect to the database to insert data it gives me this error:

An unhandled exception of type 'System.NotImplementedException' occurred in Additional information: The method or operation is not implemented.

The code I'm using is as follows:

System.Data.OleDb.OleDbConnection conn = new System.Data.OleDb.OleDbConnection();
// TODO: Modify the connection string and include any
// additional required properties for your database.
conn.ConnectionString = (@"Provider=Microsoft.ACE.OLEDB.12.0;Data source=|DataDirectory|\\crepeDB.accdb;");

conn.Open();
string query = "insert into Sales (Sdate,SQuantity) values ('" + dateTimePicker1.Value + "','" + textBox9.Text + "')";
OleDbCommand cmd = new OleDbCommand(query, conn);
cmd.ExecuteNonQuery();

This is the last thing I need to do in my project, would really appreciate any help.

Answer 1

Do not pass values for your fields concatenating them to form your command, instead use parameters.

int quantity;
if(!Int32.TryParse(textBox9.Text, out quantity))
     MessageBox.Show("Invalid number");
else
{
    using(OleDbConnection conn = new OleDbConnection(@"Provider=Microsoft.ACE.OLEDB.12.0;Data source=|DataDirectory|\\crepeDB.accdb;"))
    {    
        conn.Open();
        string query = @"insert into Sales (Sdate,SQuantity) 
                         values (@date, @qta)";
        OleDbCommand cmd = new OleDbCommand(query, conn);
        cmd.Parameters.Add("@date", OleDbType.Date).Value =  dateTimePicker1.Value;
        cmd.Parameters.Add("@qta", OleDbType.Integer).Value = quantity;
        cmd.ExecuteNonQuery();
    }
}

This is better because you don't ask someone else to convert your values from a string to the correct datatype. This automatic conversion (in particular with dates) is well know to cause problems when there is some kind of mismatch between the passed string and how the database engine interprets this string

NB I am assuming the Sdate is a field of type DateTime and SQuantity is a field of type Integer in MS-Access. If not then you can change the OleDbType Int32.TryParse to the correct matching type

Answer 2

It is basically like this . . .

con.Open();
SqlCommand cmd = new SqlCommand(@"insert into tbl_insert values(@name,@email,@add)", con);
cmd.Parameters.AddWithValue("@name", txtname.Text);
cmd.Parameters.AddWithValue("@email", txtemail.Text);
cmd.Parameters.AddWithValue("@add", txtadd.Text);
cmd.ExecuteNonQuery();
con.Close();