使用C＃从Visual Studio将数据插入Access数据库中

Question

when i try to inserting Data in an Acess Database from Visual stutio using C# i keep getting this Error "System.Data.OleDb.OleDbException: Syntax error in INSERT INTO statement."

protected void Button1_Click1(object sender, EventArgs e) {

        Guid newGUID = Guid.NewGuid();

        OleDbConnection conn = new OleDbConnection(" Provider = Microsoft.ACE.OLEDB.12.0;" + "Data Source = " + Server.MapPath("App_Data/Group.accdb"));

    OleDbCommand command = new OleDbCommand ("INSERT INTO [User] ( [Userid], [UserName], [Password], [Email], [Country], [CartID], [Address] ) VALUES (@Uname,@password,@email,@country,@address,@userid,@cartID)", conn);

    conn.Open();
                command.Parameters.AddWithValue("@userid", Convert.ToString(newGUID));
                command.Parameters.AddWithValue("@Uname", username.Text);
                command.Parameters.AddWithValue("@password", username.Text);
                command.Parameters.AddWithValue("@email", email.Text);
                command.Parameters.AddWithValue("@country", DropDownList1.SelectedItem.ToString());
                command.Parameters.AddWithValue("@cartID", Convert.ToString(newGUID));
                command.Parameters.AddWithValue("@address", address.Text); 
                command.ExecuteNonQuery();
    conn.Close();
            Response.Redirect("Login.aspx");
            Response.Write("Registration is successful");    

}

Answer 1

User is a reserved keyword. You need to enclose it between square brackets as you do for the fields

However your code has a more serious error.
Your parameters placeholders are not in the correct order in respect to the field names. So you need to fix the query and then remember that in OleDb the parameters are not recognized by their name, but by their position. Thus the code that add the parameters to collection should respect the order in which you want to retrieve the parameters value

OleDbCommand command = new OleDbCommand (@"INSERT INTO [User] 
     ( [Userid], [UserName], [Password], [Email], 
       [Country], [CartID], [Address] ) VALUES 
     ( @userid, @Uname, @password,@email,
       @country,@cartID, @address)", conn);

conn.Open();
command.Parameters.AddWithValue("@userid", address.Text);
command.Parameters.AddWithValue("@Uname", username.Text);
command.Parameters.AddWithValue("@password", username.Text);
command.Parameters.AddWithValue("@email", email.Text);
command.Parameters.AddWithValue("@country",DropDownList1.SelectedItem.ToString());
command.Parameters.AddWithValue("@cartID", address.Text);
command.Parameters.AddWithValue("@address", address.Text);
command.ExecuteNonQuery();

By the way, you are passing the username textbox to both the Username field and UserID and Password. This seems unlikely (the same for the address textbox)

Finally it seems wrong also the use of a string to set the value of the fields cartID and UserID. The method AddWithValue has no way to know what is the DataType of the field that will be updated by the parameter. So it creates a parameter based on the datatype of the value. In your case the address.Text and username.Text are string, but if the database fields expects an integer bad things will happen.
If this is the case you should be certain that you have an integer and use

command.Parameters.AddWithValue("@userid", Convert.ToInt32(address.Text));
command.Parameters.AddWithValue("@cartID", Convert.ToInt32(address.Text));

In any case it is better use the correct Add method

command.Parameters.Add("@userid", OleDbType.Integer).Value = Convert.ToInt32(address.Text));