555~~~穷死了，最后40分了，希望大家帮我看看，谢谢！

[philins]

我要实现在DataGrid中对数据库的更新，数据源是sql server中的student表,主键是Sno，现在的问题是，不能修改学号！真的是很郁闷！我看了半天代码也没有发现错误，大家帮我看看吧！谢谢了，最后的40分全给大家了，呵呵（明天就不能来了，穷死了）
update函数代码如下：
sub Stu_Update(sender as object,E as DataGridCommandEventArgs)
dim UComm as SqlCommand
dim UpdateCmd as string
dim EditText1,EditText2,EditText3 as textbox
UpdateCmd="update student set Sno=@Sno,Sname=@Sname,Sbirth=@Sbirth Where Sno=@Sno"
UComm=new SQLCommand(UpdateCmd,objConnection)

UComm.Parameters.Add(New SqlParameter("@Sno", SqlDbType.VarChar))
UComm.Parameters.Add(New SqlParameter("@Sname", SqlDbType.VarChar))
UComm.Parameters.Add(New SqlParameter("@Sbirth", SqlDbType.VarChar))

UComm.Parameters("@Sno").Value = _
StuData.DataKeys(CInt(e.Item.ItemIndex))

Dim cols() As String = {"@Sno","@Sname","@Sbirth"}
Dim numCols As Integer = E.Item.Cells.Count
'Dim i As Integer
Dim colvalue As String
Dim txtBox As Textbox

txtBox =E.Item.FindControl("txtSno")
colvalue = txtBox.Text
If (colvalue = "")
ErrorMessage.text = "ERROR: Null values not allowed for 学号"
ErrorMessage.Style("color") = "red"
Exit Sub
End If
UComm.Parameters(cols(0)).Value = colvalue

txtBox = E.Item.FindControl("txtSname")
colvalue = txtBox.Text
If (colvalue = "")
ErrorMessage.text = "ERROR: Null values not allowed for 姓名"
ErrorMessage.Style("color") = "red"
Exit Sub
End If
UComm.Parameters(cols(1)).Value = colvalue

txtBox = E.Item.FindControl("txtSbirth")
colvalue = txtBox.Text
If (colvalue = "")
ErrorMessage.text = "ERROR: Null values not allowed for 出生年月"
ErrorMessage.Style("color") = "red"
Exit Sub
End If
UComm.Parameters(cols(2)).Value = colvalue

UComm.Connection.Open()

try
UComm.ExecuteNonQuery()

Session("MyData")=nothing

StuData.EditItemIndex=-1

Catch exp as SQLexception
if exp.number=2627 then
ErrorMessage.text="已存在同样的记录"
ErrorMessage.Style("Color")="red"
Else
ErrorMessage.Text="不能更新记录"
End if
end try

'关闭连接
UComm.Connection.Close()
BindGrid()
ErrorMessage.text=""
end sub

[j99616]

UpdateCmd="update student set Sno=@Sno,Sname=@Sname,Sbirth=@Sbirth Where Sno=@Sno"

是不是有问题

[saucer]

change

update student set Sno=@Sno,Sname=@Sname,Sbirth=@Sbirth Where Sno=@Sno
===>
update student set Sname=@Sname,Sbirth=@Sbirth Where Sno=@Sno

[philins]

哦，好像是有问题，不过我如果想要同时修改Sno呢？

[lbx1979]

Sno也可以修改,不过要定义两个Parameters对应Sno,分别设置SourceVersion:
update student set Sno=@newSno,Sname=@Sname,Sbirth=@Sbirth Where Sno=@oraSno
放在where子句里的parameter要设置SourceVersion = DataRowVersion.Original
要更新的那个值就用默认的就可以了

[saucer]

UpdateCmd="update student set Sno=@Sno,Sname=@Sname,Sbirth=@Sbirth Where Sno=@OldSno"
UComm=new SQLCommand(UpdateCmd,objConnection)

UComm.Parameters.Add(New SqlParameter("@Sno", SqlDbType.VarChar))
UComm.Parameters.Add(New SqlParameter("@Sname", SqlDbType.VarChar))
UComm.Parameters.Add(New SqlParameter("@Sbirth", SqlDbType.VarChar))
UComm.Parameters.Add(New SqlParameter("@OldSno", SqlDbType.VarChar))


....
UComm.Parameters("@OldSno").Value = _
StuData.DataKeys(CInt(e.Item.ItemIndex))
....

[lbx1979]

The following code example defines an UPDATE statement in which the CustomerID column is used as a SourceColumn for two parameters: @CustomerID (SET CustomerID = @CustomerID), and @OldCustomerID (WHERE CustomerID = @OldCustomerID). The @CustomerID parameter is used to update the CustomerID column to the current value in the DataRow. As a result, the CustomerID SourceColumn with a SourceVersion of Current is used. The @OldCustomerID parameter is used to identify the current row in the data source. Because the matching column value is found in the Original version of the row, the same SourceColumn (CustomerID) with a SourceVersion of Original is used.

string updateSQL = "UPDATE Customers SET CustomerID = @CustomerID, CompanyName = @CompanyName WHERE CustomerID = @OldCustomerID";

custDA.UpdateCommand.Parameters.Add("@CustomerID", SqlDbType.NChar, 5, "CustomerID");

custDA.UpdateCommand.Parameters.Add("@CompanyName", SqlDbType.NVarChar, 40, "CompanyName");

SqlParameter myParm = custDA.UpdateCommand.Parameters.Add("@OldCustomerID", SqlDbType.NChar, 5, "CustomerID");
myParm.SourceVersion = DataRowVersion.Original;

MSDN上的例子

[saucer]

sorry, didn't see lbx1979(Love Arsenal)'s post, his solution is better

[philins]

lbx1979(Love Arsenal):
custDA?What's that?a SQLCommand?

Thank all of you VERY MUCH!
I'll pay the points now!

[ljfppp]

custDA is a SqlDataAdapter

[philins]

哦，谢谢！结帐喽！