DataBinding generates exception ???

[Chris]

Hi,

I have a DB-table 'AirplaneTypes' that has to 2 fields that form the primary
key :
'at_name' and 'at_model'
both in the DB defined as type : char 15

MyWinform client :

void Form_Load(...) {
// m_dsAirplaneTyp es1 is the DataSet
DataTable myTable = m_dsAirplaneTyp es1.AirplaneTyp es;
txtName.DataBin dings.Add("Text ", myTable, "at_name");
==> when this databind is executed will an exception be thrown from
the moment I perform an 'AcceptChanges' on my DataSet (see
below)

If this binding is not executed at Form_Load() :
no exception thrown by 'AcceptChanges' (???)

// Following DataBindings don't create any problems (only the
previous??)
txtModel.DataBi ndings.Add("Tex t", myTable, "at_model") ;
txtLength.DataB indings.Add("Te xt", myTable, "at_length" );
}

Below is the buttonInsert-click event that will generate an exception, not
after I
enter values for the first time :
txtName.Text = "1" txtModel.Text = "1" txtLength.Text = "1"
but when entering values the 2nd time :
txtName.Text = "2" txtModel.Text = "2" txtLength.Text= "2"

void btnInsert_Click (...) {
m_currentRow = m_dsAirplaneTyp es1.AirplaneTyp es.NewRow();

// Edit the fields
m_currentRow["at_name"] = txtName.Text.Tr im();
m_currentRow["at_model"] = txtModel.Text.T rim();
m_currentRow["at_length"] = txtLength.Text. Trim();

// Add to DataSet
m_dsAirplaneTyp es1.AirplaneTyp es.Rows.Add(m_c urrentRow);

// Add to DB
int n = sqlDataAdapter1 .Update(m_dsAir planeTypes1, "AirplaneTypes" );
if (n > 0)
m_dsAirplaneTyp es1.AirplaneTyp es.AcceptChange s();

==> EXCEPTION thrown when I execute the 2nd time (and I enter

different values !!)
"Column 'at_name, at_model' is constrained to be unqiue.
Value '2, 2' is already present"

BUT THE DATA HAS BEEN ENTERED IN THE DB CORRECTLY !
So 'sqlDataAdapter 1.Update() ' performs well.
}

Any help GREATLY appreciated !!

Chris

[William Ryan eMVP]

Chris, AcceptChange will end any existing edits out there, so if you had a
row in edit mode, it wouldn't be sent back to the db so the update would
work, when you call AcceptChanges, it will end the edit, reset the rowstate
etc. Make sure that the current edit is finished before calling update b/c
I think the value may be getting into the db, then when you try
AcceptChanges, it's trying to add what's already there.. Before you call
AcceptChanges, do a DataTable.Selec t on the primary key
http://www.knowdotnet.com/articles/adopartiii.html and see if that value
already exists. You may just need to do an endcurrentedit or EndEdit method
before calling update. http://www.knowdotnet.com/articles/adopartiii.html
"Chris" <ch********@pan dora.be> wrote in message
news:vd******** *************@p hobos.telenet-ops.be...

Hi,

I have a DB-table 'AirplaneTypes' that has to 2 fields that form the primary key :
'at_name' and 'at_model'
both in the DB defined as type : char 15

MyWinform client :

void Form_Load(...) {
// m_dsAirplaneTyp es1 is the DataSet
DataTable myTable = m_dsAirplaneTyp es1.AirplaneTyp es;
txtName.DataBin dings.Add("Text ", myTable, "at_name");
==> when this databind is executed will an exception be thrown from the moment I perform an 'AcceptChanges' on my DataSet (see
below)

If this binding is not executed at Form_Load() :
no exception thrown by 'AcceptChanges' (???)

// Following DataBindings don't create any problems (only the
previous??)
txtModel.DataBi ndings.Add("Tex t", myTable, "at_model") ;
txtLength.DataB indings.Add("Te xt", myTable, "at_length" );
}

Below is the buttonInsert-click event that will generate an exception, not
after I
enter values for the first time :
txtName.Text = "1" txtModel.Text = "1" txtLength.Text = "1"
but when entering values the 2nd time :
txtName.Text = "2" txtModel.Text = "2" txtLength.Text= "2"

void btnInsert_Click (...) {
m_currentRow = m_dsAirplaneTyp es1.AirplaneTyp es.NewRow();

// Edit the fields
m_currentRow["at_name"] = txtName.Text.Tr im();
m_currentRow["at_model"] = txtModel.Text.T rim();
m_currentRow["at_length"] = txtLength.Text. Trim();

// Add to DataSet
m_dsAirplaneTyp es1.AirplaneTyp es.Rows.Add(m_c urrentRow);

// Add to DB
int n = sqlDataAdapter1 .Update(m_dsAir planeTypes1, "AirplaneTypes" );
if (n > 0)
m_dsAirplaneTyp es1.AirplaneTyp es.AcceptChange s();

==> EXCEPTION thrown when I execute the 2nd time (and I enter

different values !!)
"Column 'at_name, at_model' is constrained to be unqiue.
Value '2, 2' is already present"

BUT THE DATA HAS BEEN ENTERED IN THE DB CORRECTLY !
So 'sqlDataAdapter 1.Update() ' performs well.
}

Any help GREATLY appreciated !!

Chris