Develop Reference

Data gets duplicated in datagridview when query applied?

I am trying to perform CRUD operation on winform
This is for ASP.NET winform in which whenever I try to insert, update or delete the data to or from the database first of all rows and inside content gets duplicated
https://imgur.com/a/d5jgv6H
however, upon restarting the application data shows up correctly
private void button2_Click(object sender, EventArgs e)
{
//insert
try
{
con.Open();
//.text property gets/Sets text associated with this control
String name = textBox1.Text.ToString();
String address = textBox2.Text.ToString();
String number = textBox3.Text.ToString();
long pnumber = Int64.Parse(number);
String sem = textBox4.Text.ToString();
long semester = Int64.Parse(sem);
string branch = comboBox1.SelectedItem.ToString();
String query = "insert into student values('" + name + "','" + address + "'," + pnumber + "," + semester + ",'" + branch + "')";
SqlCommand sqlcom = new SqlCommand(query, con);
int i = sqlcom.ExecuteNonQuery();
if (i >= 1)
{
MessageBox.Show("Student has been Registered: " + name);
}
else
{
MessageBox.Show("Registration Failed ! ");
}
//clearing data
button1_Click(sender, e);
show();
con.Close();
}
catch (Exception exp)
{
MessageBox.Show("Error is : " + exp.ToString());
}
}
void show()
{
String query = "select * from student";
SqlDataAdapter adapter = new SqlDataAdapter(query, con);
DataTable dataInTable = new DataTable();
adapter.Fill(dataInTable);
//DataRow represents row of data in DataTable
foreach (DataRow item in dataInTable.Rows)
{
int n = dataGridView1.Rows.Add();
dataGridView1.Rows[n].Cells[0].Value = item[0].ToString();
dataGridView1.Rows[n].Cells[1].Value = item[1].ToString();
dataGridView1.Rows[n].Cells[2].Value = item[2].ToString();
dataGridView1.Rows[n].Cells[3].Value = item[3].ToString();
dataGridView1.Rows[n].Cells[4].Value = item[4].ToString();
}
}
The query works fine but rows still get duplicated. What's the problem?
I can't find any bug, so I assume I am doing something incorrectly.

Your show method adds rows to the grid, but it never removes the rows which are already in the grid.
Normally one would use data binding to populate a DataGridView or other data-bound controls. I'm going to assume you have reasons for just adding rows directly (perhaps it's simpler for your needs) and not change that. Given that structure, probably the easiest thing to do is just to clear the grid before adding the new rows:
void show()
{
String query = "select * from student";
SqlDataAdapter adapter = new SqlDataAdapter(query, con);
DataTable dataInTable = new DataTable();
adapter.Fill(dataInTable);
dataGridView1.Rows.Clear(); // <--- here
foreach (DataRow item in dataInTable.Rows)
{
int n = dataGridView1.Rows.Add();
dataGridView1.Rows[n].Cells[0].Value = item[0].ToString();
dataGridView1.Rows[n].Cells[1].Value = item[1].ToString();
dataGridView1.Rows[n].Cells[2].Value = item[2].ToString();
dataGridView1.Rows[n].Cells[3].Value = item[3].ToString();
dataGridView1.Rows[n].Cells[4].Value = item[4].ToString();
}
}
That way any time you are about to populate the grid with new data, you first clear the existing data from it.

C# datagrid not populating and no error

My first problem is that i have a method private void FillGeneralLedger(), i put the method in a button on click event to fill a datagridview dgvGeneralLedger my problem is when i run i am not getting an error and the dgv is remaining empty.
My Second problem is i would like to use the same connection but have 5 commands all the same just different account numbers eg in the example below the account below is '8200030' i would like to do the same for '8200031','8200032'
private void FillGeneralLedger()
{
SqlConnection conn = new SqlConnection(sConnectionString);
try
{
DataSet dataset = new DataSet();
SqlCommand command = new SqlCommand("Select Ddate as Date" +
", etype" +
", Refrence" +
", linkacc as ContraAcc" +
", Description" +
", sum(case when amount > 0 then amount else 0 end) as Debits" +
", sum(case when amount < 0 then amount else 0 end) as Credits" +
", sum(amount) as Cumulative" +
" FROM dbo.vw_LedgerTransactions " +
" WHERE accnumber = '8200030'" +
" AND DDate BETWEEN '2016-04-01 00:00:00' AND '2016-04-30 00:00:00'" +
" AND DataSource = 'PAS11CEDCRE17'" +
" group by Ddate, etype, Refrence, linkacc, Description, Amount", conn);
SqlDataAdapter adapter = new SqlDataAdapter(command);
conn.Open();
command.ExecuteNonQuery();
adapter.Fill(dataset);
if (dataset.Tables[0].Rows.Count != 0)
{
lstGeneralLedger = new List<ReportDataClasses.GeneralLedger>();
foreach (DataRow row in dataset.Tables[0].Rows)
{
ReportDataClasses.GeneralLedger newGeneralLedger = new ReportDataClasses.GeneralLedger();
newGeneralLedger.Ddate = row[0].ToString();
newGeneralLedger.etype = row[1].ToString();
newGeneralLedger.refrence = row[2].ToString();
newGeneralLedger.linkacc = row[3].ToString();
newGeneralLedger.Description = row[4].ToString();
newGeneralLedger.debit = decimal.Parse(row[5].ToString());
newGeneralLedger.credit = decimal.Parse(row[6].ToString());
newGeneralLedger.cumulative = decimal.Parse(row[7].ToString());
lstGeneralLedger.Add(newGeneralLedger);
}
dgvGeneralLedger.DataSource = dataset;
dgvGeneralLedger.Columns[0].Visible = false;
pdfCreator.AddGeneralLedgerPage(lstGeneralLedger, 1);
}
}
catch (Exception ex)
{
MessageBox.Show("Application Error. err:" + ex.ToString());
}
finally
{
conn.Close();
}
}

Why do you use a DataSet when you only need a single DataTable, this doesn't make any sense. Just use one DataTable:
DataTable dataTableSource = new DataTable();
adapter.Fill(dataTableSource);
// .. cotinue your code
dgvGeneralLedger.DataSource = dataTableSource;
Account Number issue:
You can use SqlParameter instead of hard-coding the value. Like this:
command.Parameters.AddWithValue("#acc", "8200030");
dataTableSource.Load(command.ExecuteReader())
// .. store results ..
// second account
command.Parameters["#acc"].Value = "8200031";
dataTableSource.Load(command.ExecuteReader())
// continue with the rest
But you need to change your query to be like this:
"... WHERE accnumber = #acc ...."

How to display Access data in a DataTable in C#?

I'm new to C#. I'm having a difficult time displaying my Access data in a DataTable. Here is the code:
try
{
reader.Read();
for (int i = 0; i < 16; i++)
{
if (selectedCourse == reader["CourseName"].ToString())
{
match = true;
}
else
{
match = false;
}
}
if (match == true)
{
tabControl.SelectedTab = tabPage1; // opens results page
string connString = #"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\Users\...454_Database.accdb";
DataTable results = new DataTable();
using (OleDbConnection conn = new OleDbConnection(connString))
{
OleDbCommand cmd = new OleDbCommand("Select c.PeriodID, c.CourseName, c.Teacher, t.Room"
+ "FROM Courses c JOIN Teacher t ON t.TeacherID = c.TeacherID"
+ "WHERE [CourseName] ='" + cboxClass.Text + "'", conn);
conn.Open();
OleDbDataAdapter adapter = new OleDbDataAdapter(cmd);
adapter.Fill(results);
dataTblResults.DataSource = results;
I can tell the data is being compared to the db and it correctly determines if the query has results or not. However, when there are results, they do not get displayed on the data table. Is it because it doesn't know which columns correspond to the columns in the data table?
Thanks in advance!

How is your datagrid configured?
Try setting: (before setting the DataSource)
dataTblResults.AutoGenerateColumns = true;
dataTblResults.DockStyle.Fill = DockStyle.Fill;

Try using a Dataset first. Then turn it to a datatable
DataSet ds = new DataSet();
adapter.fill(ds)
if (ds.Tables[0].Rows.Count >= 1)
{
results = ds.Tables[0];
}
dataTblResults.DataSource = results;
I dont think this is what you are looking for but maybe it'll bring you closer to the answer

Using DataTable.update() does not add entries to my SQL Server database in one method but does in another

I have a method (AddRowToSQLTable()) that is passed a row, it then creates a row array containing that row and then passes it to DataTable.update().
This works fine. The SQL Server is updated and the next time I run (debug) the program the new data is present.
Another method (AddStock()) uses a similar structure but does not work.
The difference being that I am passing a data table in Update() not a Row[] however no exception is thrown just nothing is updated/added on the server.
Can someone please explain what exactly is going on and why these differ? I would like to know this even if the solution is to use a different structure to achieve what I want so I know for the future and have a better understanding.
To Note:
I have tested to ensure the DataTable being passed contains records. The DataTable is of the same format as the target SQL Server table.
I have also tried SqlBulkCopy and encounter the same problem.
Many thanks!
private DataTable StockAdditions;
public void PrepareStockQuantitiesForAdding()
{
if (StockAdditions != null)
{
StockAdditions.Clear();
}
StockAdditions = StockQuantitiesTable.Clone();
int Count = 0;
DataRow RowToAdd = StockQuantitiesTable.NewRow();
DataView AreaIDs = new DataView(AreaTable);
DataView Conditions = new DataView(ConditionsTable);
int AreaID;
string ConditionCode;
foreach (DataRow Row in SessionSKUScanned.Rows)
{
if (Row["Serial Number"].ToString() == "")
{
Conditions.RowFilter = "([Name] = '" + Row["Condition"] + "')";
ConditionCode = Conditions[0][2].ToString();
AreaIDs.RowFilter = "([StorageAreaName] = '" + Row["Area"] + "')";
AreaID = Convert.ToInt32(AreaIDs[0][0]);
DataView StockQuantities = new DataView(StockQuantitiesTable);
StockQuantities.RowFilter = "([QuantityID] = '" + AreaID + "-" + Row["SKU"] + "-" + ConditionCode + "')";
if (StockQuantities.Count > 0)
{
StockQuantities[0][3] = Convert.ToInt32(StockQuantities[0][3]) + 1;
RowToAdd["QuantityID"] = AreaID + "-" + Row["SKU"] + "-" + ConditionCode;
RowToAdd["SKU"] = Row["SKU"];
RowToAdd["AreaID"] = AreaID;
RowToAdd["Quantity"] = StockQuantities[0][3] = Convert.ToInt32(StockQuantities[0][3]) + 1;
RowToAdd["Condition"] = Row["Condition"];
}
else
{
RowToAdd["QuantityID"] = AreaID + "-" + Row["SKU"] + "-" + ConditionCode;
RowToAdd["SKU"] = Row["SKU"];
RowToAdd["AreaID"] = AreaID;
RowToAdd["Quantity"] = 1;
RowToAdd["Condition"] = Row["Condition"];
}
Count++;
}
else
{
RowToAdd["QuantityID"] = Row["Serial Number"];
RowToAdd["SKU"] = Row["SKU"];
AreaIDs.RowFilter = "([StorageAreaName] = '" + Row["Area"] + "')";
RowToAdd["AreaID"] = Convert.ToInt32(AreaIDs[0][0]);
RowToAdd["Quantity"] = 1;
RowToAdd["Condition"] = Row["Condition"];
Count++;
}
StockQuantitiesTable.ImportRow(RowToAdd);
MessageBox.Show(RowToAdd[0].ToString());
StockAdditions.ImportRow(RowToAdd);
}
}
private void AddRowToSQLTable(DataRow Row, string SQLTableName)
{
DataRow[] Rows = new DataRow[1];
Rows[0] = Row;
SqlConnection SQLConn = new SqlConnection(ConfigurationManager.ConnectionStrings["eCommStock.Properties.Settings.Demo_SiteConnectionString"].ConnectionString);
SQLConn.Open();
SqlDataAdapter daUpdateTable = new SqlDataAdapter("Select * From " + SQLTableName, SQLConn);
SqlCommandBuilder SQLcmdBuilder = new SqlCommandBuilder(daUpdateTable);
daUpdateTable.Update(Rows);
SQLConn.Close();
}
public void AddStock()
{
SqlConnection SQLConn = new SqlConnection(ConfigurationManager.ConnectionStrings["eCommStock.Properties.Settings.Demo_SiteConnectionString"].ConnectionString);
SQLConn.Open();
SqlDataAdapter daUpdateTable = new SqlDataAdapter("Select * From StockQuantities", SQLConn);
SqlCommandBuilder SQLcmdBuilder = new SqlCommandBuilder(daUpdateTable);
daUpdateTable.Update(StockAdditions);
SQLConn.Close();
}

It doesn't work because RowToAdd.RowState is Detached. I don't like it, but the following is a quick and dirty solution, before importing the row to StockAdditions, make sure the row is in Added state, later you can "detach" the row again.
StockQuantitiesTable.Rows.Add(RowToAdd);
StockAdditions.ImportRow(RowToAdd);
StockQuantitiesTable.Rows.Remove(RowToAdd);

Date-picker using select statement oracle

I'm trying to implement date-picker functionality in my project, but I can't do it quite right. I'm trying to pass the date-picker value in my oracle string so that it will compare with my db column and return results on the date criteria...
Whenever I pass it to the select statement it won't generate errors particularly but on button click it doesn't perform anything except it shows "not connected".
str = "Select * from sania.doctor where APPOINTMENT_DATE = "+ datepicker1.value;
It is clear it is logical mistake but I'm new to this C# concepts I need someone to tell me how to pass it and then display the results as well.
private void button1_Click(object sender, EventArgs e)
try
{
OracleCommand com;
OracleDataAdapter oda;
string ConString = "Data Source=XE;User Id=system;Password=sania;";
OracleConnection con = new OracleConnection(ConString);
{
// string id = dateTimePicker1.Text.Trim();
con.Open();
// str = "Select * from sania.doctor where APPOINTMENT_DATE = " + dateTimePicker1.value;
str = "select * from sania.doctor where APPOINTMENT_DATE to_date('"+dateTimePicker1.Value.ToString("yyyyMMdd") + "', 'yyyymmdd')";
com = new OracleCommand(str);
oda = new OracleDataAdapter(com.CommandText, con);
dt = new DataTable();
oda.Fill(dt);
Rowcount = dt.Rows.Count;
//int val = 0;
for (int i = 0; i < Rowcount; i++)
{
dt.Rows[i]["APPOINTMENT_DATE"].ToString();
//if (id == dateTimePicker1.Value)// this LINE SHOWS ERROR--because it is a string and I am using date with it. Don't know conversion
// {
// val = 1;
//}
}
// if (val == 0)
// { MessageBox.Show("INVALID ID"); }
// else
// {
DataSet ds = new DataSet();
oda.Fill(ds);
if (ds.Tables.Count > 0)
{
dataGridView1.DataSource = ds.Tables[0].DefaultView;
}
else { MessageBox.Show("NO RECORDS FOUND"); }
}
}
//}
catch (Exception)
{ MessageBox.Show("not connected"); }
}

Do not put values into SQL directly, use bind variables/parametes instead. For Oracle:
// :prm_Appointment_Date bind variable declared within the query
String str =
#"select *
from sania.doctor
where Appointment_Date = :prm_Appointment_Date";
....
using(OracleCommand q = new OracleCommand(MyConnection)) {
q.CommandText = str;
// datepicker1.Value passed into :prm_Appointment_Date via parameter
q.Parameters.Add(":prm_Appointment_Date", datepicker1.Value);
...
}
Doing like that you can be safe from either SQL Injection or Format/Culture differences