I am new to c# and try to bind a datagridview to a mssql database in visual studio 2010. The databindings are OK and everything seems to work. Except for a few strange errors:
I get the error in the subject after: updating the same row 2 times, deleting a new inserted row, after updating a row when an other row was deleted (word changes to DeleteCommand)
None of the solutions I found on Google workes for me. I hope someone can help me with this. Here is te code:
private void fillDatagrid()
{
//fill datagrid ADO.NET
conn = new SqlConnection(TestApp.Properties.Settings.Default.TestdatabaseConnectionString);
cmd = conn.CreateCommand();
conn.Open();
cmd.CommandText = "SelectFrom";
cmd.CommandType = CommandType.StoredProcedure;
cmd.Parameters.Add("@table", SqlDbType.NVarChar, 50).Value = "Countries";
cmd.Parameters.Add("@filters", SqlDbType.NVarChar, 300).Value = "";
adapt = new SqlDataAdapter(cmd);
dt = new DataTable();
adapt.Fill(dt);
dt.TableName = "Countries";
conn.Close();
BindingSource src = new BindingSource();
src.DataSource = dt;
dt.RowChanged += new DataRowChangeEventHandler(dt_RowChanged);
dgDatabaseGrid.DataSource = src;
dgDatabaseGrid.AutoResizeColumns(DataGridViewAutoSizeColumnsMode.AllCells);
//dgDatabaseGrid.RowValidating += new DataGridViewCellCancelEventHandler(dgDatabaseGrid_RowValidating);
//disable columns:
dgDatabaseGrid.Columns[0].Visible = false;
dgDatabaseGrid.Columns["date_insert"].Visible = false;
dgDatabaseGrid.Columns["user_insert"].Visible = false;
dgDatabaseGrid.Columns["date_change"].Visible = false;
dgDatabaseGrid.Columns["user_change"].Visible = false;
dgDatabaseGrid.Columns["deleted"].Visible = false;
//auto size last column
dgDatabaseGrid.Columns["remarks"].AutoSizeMode = DataGridViewAutoSizeColumnMode.Fill;
SqlCommandBuilder cb = new SqlCommandBuilder(adapt);
}
void dt_RowChanged(object sender, DataRowChangeEventArgs e)
{
try
{
adapt.Update(dt);
}
catch (SqlException ex)
{
Debug.WriteLine(ex.Message);
}
}
private void dgDatabaseGrid_UserDeletingRow(object sender, DataGridViewRowCancelEventArgs e)
{
if (!e.Row.IsNewRow)
{
DialogResult response = MessageBox.Show("Are you sure?", "Delete row?",
MessageBoxButtons.YesNo,
MessageBoxIcon.Question,
MessageBoxDefaultButton.Button2);
if (response == DialogResult.Yes)
{
//ipv delete --> deleted=1
conn.Open();
cmd = conn.CreateCommand();
cmd.CommandType = CommandType.StoredProcedure;
cmd.CommandText = "DeleteFrom";
cmd.Parameters.Add("@table", SqlDbType.NVarChar, 50).Value = "Countries";
cmd.Parameters.Add("@id", SqlDbType.Int).Value = e.Row.Cells[0].Value;
cmd.ExecuteNonQuery();
conn.Close();
//delete from datagrid:
dt.Rows[dgDatabaseGrid.SelectedCells[0].RowIndex].Delete();
}
//always cancel!
e.Cancel = true;
}
}
Solution. A concurrency violation essentially means that the row in the database could not be added. In the case of saving a record, this refers to the fact that the information contained in the record could not be added to one of more of the database tables that are supposed to receive the information.
Concurrency exceptions (System. Data. DBConcurrencyException) are raised when two users attempt to change the same data in a database at the same time.
I know it's very late but maybe it will help someone.
Made the following changes to your code:
try
{
adapt.Update(dt);
Put these lines here and use your variable
Me.yourTableAdapter.Update(Me.yourDataSet.yourTable)
Me.yourDataSet.youTable.AcceptChanges()
Me.yourTableAdapter.Fill(Me.yourDataSet.yourTable)
it worked like a charm for me hope it will work for you.
}
catch (SqlException ex)
{
Debug.WriteLine(ex.Message);
}
after updating the same row 2 times
Is there a Timestamp column (or any other column that is changed/filled on the Db server) ?
Your problem could happen when the in-memory row is different from what's in the Db. And because you use a SP for the SelectCmd there (probably) is no refresh after an update.
after deleting a new inserted row
Similar, caused not fetching the new Id after an insert
after updating a row when an other row was deleted (word changes to DeleteCommand)
totally unclear.
But why do you Delete rows 'manually' instead of leaving it to the adapt.Update() ? And are you sure that not both methods are executed?
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