Re: A couple of questions about updating data through a dataset

I finally figured out what I was doing wrong. I had used the DataRowVersion
enumeration for the SourceVersion of the SqlParameter object, but I had not
assigned the SourceColumn for the SqlParameter object. Once I assigned
that, then it worked fine. (BTW, I didn't use BeginEdit(), and it still
worked fine.)

Rod


"Rod" <rodf@xxxxxxxxxxxxxxxxx> wrote in message
news:%23eyaqPpcFHA.2128@xxxxxxxxxxxxxxxxxxxxxxx
> Thank you, W.G. for replying. My reply is in-line (towards the bottom):
>
>
> "W.G. Ryan eMVP" <WilliamRyan@xxxxxxxxx> wrote in message
> news:uPGOixfcFHA.720@xxxxxxxxxxxxxxxxxxxxxxx
>>> DataRow r = DataTable.Rows[0];
>>>
>>> and the row has a column named FirstName, can I do this:
>>>
>>> r["FirstName"] = "Rod";
>>>
>>> or do I have to do something like this first:
>>>
>>> r.BeginEdit();
>>> r["FirstName"] = "Rod";
>>>
>>> And if I do have to use the BeginEdit() method, do I also have to issue
>>> the EndEdit() method? Or will that basically clear the row's Current
>>> view and reassign that to the Original view?
>>
>> If you are doing this programatically, then no you don't. THe problme is
>> that when you use the UI, often it will start the beginedit but nothing
>> triggers the end edit. HOwever, I'd highly recommed that you do use
>> beginedit. If you don't, then for instance, if your values are sorted, it
>> could affect the sort immediately.
>>
>>>
>>> I know that the datarow's SourceVersion will come into play, but I am
>>> not sure how.
>>>
>>> Second question: What DOES the Update() method of the SqlDataAdapter
>>> really work on? For example, after struggling with this for half the
>>> day I finally got rid of the error message I was getting saying,
>>>
>>> "Procedure 'spMyProc' expects parameter '@FirstName', which was not
>>> supplied"
>>>
>>> to go away, but now when I assign a value to the datarow's FirstName
>>> column, then I would have expected that to actually be saved to the
>>> database when I issued the SqlDataAdapter's Update() method. Instead,
>>> it just quietly goes about its business and nothing at all is
>>> saved/updated. So, what I am doing wrong now?
>>>
>>> Rod
>>
>> Update goes through each row and looks at the RowState. If it's modified,
>> added, deleted, then it looks to the corresponding command and fires it.
>> If you look at the overload for a dataColumn DataColumn dc = new
>> DataColumn("ColumnName", typeof(Whatever), Column). This is the value
>> that will map back to the parameter if you've coded your CRUD correctly
>> or of you had it generated. IF you don't have any changeds, you can call
>> Update all year and nothing will happen. If you call Update and you have
>> modified rows but no update command, you'll get an exception. It maps
>> those values back to the params.
>>
>> Does this answer your question?
>
> Almost. I will modify a column in the dataset, but then when I call the
> Update() method of the SqlDataAdapter it doesn't save/change anything. I
> don't understand how I could modify the value but then the Update() not
> work.
>
> BTW, I am doing this programmatically, rather than using any wizard like
> the CommandBuilder.
>
>> BTW< I'd highly encourage using a Keyed table, and using the DataAdapter
>> Configuration wizard and deconstructing what it created. You'll learn a
>> lot - or at least, I did.
>>
>> --
>> W.G. Ryan, MVP
>>
>
>


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