Re: DataTable, not writing to database

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From: Sergey Bogdanov (sergey.bogdanov_at_gmail.com)
Date: 03/24/05 

Date: Fri, 25 Mar 2005 00:38:08 +0200

I have written for you the example:
http://www.sergeybogdanov.com/Samples/SQLCeTest.zip

Best regards,
Sergey Bogdanov
http://www.sergeybogdanov.com

Mike wrote:
> Well, that seems to be an improvement. The dataview now recognizes Modified
> rows. The data I manually insert into the table is going in fine via....
>
> DataTable.DefaultView(Me.BindingContext(DataTable).Count - 1)("SampleID") =
> g_SampleID
>
> But...the data entered via my bound controls are not.
>
> After I "EndCurrentEdit" I clear the DataTable and Requery the DataTable. I
> have records (because of the data I entered manually) but none of the records
> from my bound fields got saved. In other words I have blank records on my
> form. They are all null. Surgey, can you think of any reason this may be
> happening? I dont know what else to try?
>
> I have done this a million times and have always had it work fine. The only
> difference here is that I am clearing the dataset and requerying the database
> for the bound form. It obviously must have something to do with that.
>
>
> "Sergey Bogdanov" wrote:
>
>
>>You did not say that you were adding new rows. Then you must modify
>>DataView in this manner:
>>
>>Dim dv As DataView = new DataView(table, Nothing, Nothing,
>>DataViewRowState.ModifiedCurrent or DataViewRowState.Added)
>>
>>Instead of direct access to DataTable use DefaultView and for commiting
>>editing call EndCurrentEdit:
>>
>>
>>BindingContext(DataTable).AddNew()
>>DataTable.DefaultView(BindingContext(table).Count - 1)("SampleID") =
>>m_SampleID
>>....
>>BindingContext(DataTable).EndCurrentEdit()
>>
>>
>>
>>Best regards,
>>Sergey Bogdanov
>>http://www.sergeybogdanov.com
>>
>>
>>Mike wrote:
>>
>>>No problem, your little snippet is pretty much how I do it.
>>>
>>>'I first create a new record
>>>Me.BindingContext(DataTable).AddNew()
>>>
>>>'I then insert some data, like the primary key, into the row.
>>>DataTable.Rows(Me.BindingContext(DataTable).Count - 1)("SampleID") =
>>>m_SampleID
>>>
>>>'The rest of the data is inserted via the bound controls (i.e. TextBoxes,
>>>Combobox's, etc.) on the form.
>>>
>>>'Then, to reiterate, I update the Data Table (unsuccesfully)
>>>DataAdapter.Update("DataTable")
>>>
>>>Does that help?
>>>
>>>"Sergey Bogdanov" wrote:
>>>
>>>
>>>
>>>>Please show us code snippet how you modify data rows in the DataTable.
>>>>It should be something like this:
>>>>
>>>>DataTable.Rows(0)("column") = value
>>>>
>>>>
>>>>Best regards,
>>>>Sergey Bogdanov
>>>>http://www.sergeybogdanov.com
>>>>
>>>>
>>>>Mike wrote:
>>>>
>>>>
>>>>>Thanks Sergey-
>>>>>
>>>>>Well, your dataview suggestion seemed to identify the problem! Using the
>>>>>dataview to only show 'ModifiedCurrent' records returns a count of 0. Any
>>>>>idea why? Before I clear the DataTable I can see that there are records in
>>>>>the DataTable, I can even see all the values in each row. But I still get no
>>>>>'ModifiedCurrent' records via the DataView.
>>>>>
>>>>>What triggers the DataViewRowState in a Datatable?
>>>>>
>>>>>Any suggestions would be extremely helpful!
>>>>>
>>>>>Thanks
>>>>>
>>>>>
>>>>>
>>>>>"Sergey Bogdanov" wrote:
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>>Though you would get an InvalidOperationException... Post your Update
>>>>>>command and also make sure that you have modified these records. See
>>>>>>what records have been returned by:
>>>>>>
>>>>>>Dim dv as DataView = new DataView(DataTable, Nothing, Nothing,
>>>>>>DataViewRowState.ModifiedCurrent)
>>>>>>
>>>>>>
>>>>>>Best regards,
>>>>>>Sergey Bogdanov
>>>>>>http://www.sergeybogdanov.com
>>>>>>
>>>>>>
>>>>>>Sergey Bogdanov wrote:
>>>>>>
>>>>>>
>>>>>>
>>>>>>>Have you set the DataAdapter.UpdateCommand before DataAdapter.Update
>>>>>>>invocation?
>>>>>>>
>>>>>>>Best regards,
>>>>>>>Sergey Bogdanov
>>>>>>>http://www.sergeybogdanov.com
>>>>>>>
>>>>>>>
>>>>>>>Mike wrote:
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>>I am having problems getting records to save to a DataTable and was
>>>>>>>>hoping maybe someone out there could help. I am using a DataTable
>>>>>>>>that is bound to a data entry form. Basically, here is how it flows....
>>>>>>>>
>>>>>>>>1.) DataTable has several records in it. 2.) User pushes a button to
>>>>>>>>signal that they are done with the current record (and therefore dont
>>>>>>>>want to see it anymore) and a flag is inserted in the record to
>>>>>>>>indicate this.
>>>>>>>>3.) I want to commit all the current records in the DataTable to the
>>>>>>>>database and requery the database so that it brings up a fresh
>>>>>>>>datatable (minus the record the user just said they were done with).
>>>>>>>>
>>>>>>>>This is the code I am using
>>>>>>>>
>>>>>>>>'Trying to commit the changes to the database
>>>>>>>>DataAdapter.Update(DataTable)
>>>>>>>>DataTable.AcceptChanges()
>>>>>>>>
>>>>>>>>'Clear the current DataTable
>>>>>>>>DataTable.Clear
>>>>>>>>
>>>>>>>>'Requery Database
>>>>>>>>cmd.CommandText = MySqlStatement
>>>>>>>>DataAdapter= New AdoceDataAdapter(cmd)
>>>>>>>>DataAdapter.Fill(DataTable)
>>>>>>>>
>>>>>>>>But when I do this, I dont get any records to return because the never
>>>>>>>>got wrote to the database? Any suggestions?
>>>>>>>>
>>>>>>>>Thanks!
>>>>>>>>
>>>>>>>>Mike
>>>>>>>>
>>>>>>

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