嗨索菲亚，

在更新语句中，在查询中添加@RollNo参数。

检查您的变量_FirstName，_LastName，_CollegeName等使用最新值更新，RollNo字段未添加到参数列表中

 cmd.Parameters .AddWithValue（  @ Fname，_ FirstName）; 
 cmd.Parameters.AddWithValue（  @ Lname，_ LastName）; 
 cmd.Parameters.AddWithValue（  @ Clgname，_ CollegeName）; 
 cmd.Parameters.AddWithValue（  @ Mark，_ MarksObtained）; 
 cmd.Parameters.AddWithValue（  @ Exam，_ Exam）; 
 cmd.Parameters.AddWithValue（  @ RollNo;，?????）; //修改此项line  

什么是stud变量在这里做什么？而且你没有使用stud var值来更新语句。检查一下

Hi ,

I have create a table "StudentsInformation" in ms access 2007 database.I successfully established the connection also with WPF and ms access 2007.
I am able to add new records in to the table and i am able to view the records also .

The problem is i am unable to update one row.

If i make one change in one field in one row ,it gets reflected in all the rows.

For ex:

if update last name for a particular record ,the last name gets updated in all records.

Please help.

Please find the below mentioned code

My class name is Students.cs

public void Update()
{
OleDbConnection con = new OleDbConnection ("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\\Users\\SR0150\\Documents\\Students.accdb");
con.Open();
OleDbCommand cmd = new OleDbCommand("Update StudentInformation set Fname=@Fname,Lname=@Lname,Clgname=@Clgname,Mark=@Mark Where RollNo=@RollNo",con);
//assign the values and add parameters
cmd.Parameters.AddWithValue("@Fname", _FirstName);
cmd.Parameters.AddWithValue("@Lname", _LastName);
cmd.Parameters.AddWithValue("@Clgname", _CollegeName);
cmd.Parameters.AddWithValue("@Mark", _MarksObtained);
cmd.Parameters.AddWithValue("@Exam", _Exam);
cmd.ExecuteNonQuery();
}

My MainWindow.xaml.cs code

private void btnUpDate_Click(object sender, RoutedEventArgs e)
{
stud.RollNo = Convert.ToInt32(txtRollNo.Text);
stud.FirstName = txtFirstName.Text;
stud.LastName = txtLastName.Text;
stud.CollegeName = txtClgName.Text;
stud.MarksObtained = txtMarks.Text;
stud.Exam = txtExamResults.Text;
stud.Update();//call object for update record
MessageBox.Show("Update Record", "Update");
}

Thanks
Sophia

Hi sophia,
In update statement add the @RollNo parameter in your query.

Check your variables _FirstName, _LastName, _CollegeName etc are updated with recent values and RollNo field is not added to the parameters list

cmd.Parameters.AddWithValue("@Fname", _FirstName);
cmd.Parameters.AddWithValue("@Lname", _LastName);
cmd.Parameters.AddWithValue("@Clgname", _CollegeName);
cmd.Parameters.AddWithValue("@Mark", _MarksObtained);
cmd.Parameters.AddWithValue("@Exam", _Exam);
cmd.Parameters.AddWithValue("@RollNo;, ?????); // Modify this line

what is stud variable doing here? and you are not using stud var value to update statement. check that too.