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C# - How to use ListView and SQLite database

I'm trying to add some data from a SQLite database, inside a ListView.
I'm having some difficulties as I want to insert all the data of the column and not a single record.
TEST CODE:
Form1.cs {Load}
private void home_form_Load(object sender, EventArgs e)
{
listView1.Refresh();
listView1.View = View.Details;
listView1.Columns.Add("ID");
listView1.Columns.Add("Grado");
listView1.Columns.Add("Cognome");
listView1.Columns.Add("Nome");
listView1.Columns.Add("Status");
}
Form1.cs {menu_button_gestionepax}
private void menu_button_gestionepax_Click(object sender, EventArgs e)
{
menu_button_dashboard.BackColor = System.Drawing.Color.DeepSkyBlue;
panel_dashboard.Visible = false;
gestionepersonale_panel.Visible = true;
menu_button_gestionepax.BackColor = System.Drawing.Color.Blue;
listView1.Refresh();
ListViewItem lst = new ListViewItem();
lst.SubItems.Add(LoadUsers.ManagerFind());
lst.SubItems.Add(LoadUsers.ManagerFind());
lst.SubItems.Add(LoadUsers.ManagerFind());
lst.SubItems.Add(LoadUsers.ManagerFind());
lst.SubItems.Add(LoadUsers.ManagerFind());
listView1.Items.Add(lst);
/*
string[] row = { LoadUsers.ManagerFindid(), LoadUsers.ManagerFindid() };
var listViewItem = new ListViewItem(row);
infobox_listview.Items.Add(listViewItem);
*/
}
LoadUsers.cs
public dynamic string ManagerFind()
{
using (IDbConnection cnn = new SQLiteConnection(LoadConnectionString()))
{
var select = cnn.Query($"select id from utenti");
if (select.Any())
{ return select[0].ToString(); }
else return "wrong";
}
}
I have also done various other tests and one of the difficulties in some cases is to call string ManagerFind() from LoadUsers.cs

Try something like this to get your rows and columns from your sql i know this is how you do it in SQL im sure there is a similar way to do it with sqlLite
using (SqlConnection connection = new SqlConnection(_sqlConnectionStringFromUserImput))
{
connection.Open();
if (connection.State == ConnectionState.Open)
{
SqlCommand sqlCommand =
new SqlCommand(
"select id from utenti",
connection)
{
CommandType = CommandType.Text,
CommandTimeout = 20
};
SqlDataReader reader = sqlCommand.ExecuteReader();
if (reader.HasRows)
{
while (reader.Read())
{
DateTime datetimefield = reader.GetFieldValue<DateTime>(0);
string stringField = reader.GetFieldValue<string>(1);
}
}
reader.Close();
}
connection.Close();
}

ProductInsert() does not exist in current context

protected void Btn_CheckOut_Click(object sender, EventArgs e)
{
int result = 0;
Payment user = new Payment(txt_CardNumber.Text, txt_CardHolderName.Text, txt_ExpirationDate.Text, txt_Cvv.Text);
result = ProductInsert();
/* Session["CardNumber"] = txt_CardNumber.Text;
Session["CardHolderName"] = txt_CardHolderName.Text;
Session["ExpirationDate"] = txt_ExpirationDate.Text;
Session["Cvv"] = txt_Cvv.Text;*/
Response.Redirect("Payment Sucessful.aspx");
}
public int ProductInsert()
{
int result = 0;
string queryStr = "INSERT INTO CustomerDetails(CardNumber, CardHolderName, ExpirationDate, Cvv)"
+ "values (#CardNumber,#CardHolderName, #ExpirationDate, #Cvv)";
try
{
SqlConnection conn = new SqlConnection(connStr);
SqlCommand cmd = new SqlCommand(queryStr, conn);
cmd.Parameters.AddWithValue("#CardNumber", this.CardNumber);
cmd.Parameters.AddWithValue("#CardHolderName", this.CardHolderName);
cmd.Parameters.AddWithValue("#ExpirationDate", this.ExpirationDate);
cmd.Parameters.AddWithValue("#Cvv", this.Cvv);
conn.Open();
result += cmd.ExecuteNonQuery(); // Returns no. of rows affected. Must be > 0
conn.Close();
return result;
}
catch (Exception ex)
{
return 0;
}
}
}
I am trying to store credit card informations into database. I have created a productInsert() method and now I am trying to insert whatever values into the database.
This code is giving the error:
ProductInsert() does not exist in current context

How to successfully fill the datagridview - getting error invalid attempt to call read when reader is closed in C#

I need a quick help. I am getting an error invalid attempt to call read when reader is closed when trying to add my databagridview from the reader.
the databases is a class that calls the database connection string. and the databaseColumn is a class that has all columns names.
error for column Time_Completed
what is the issues please help
Here is the code:
//datagridview, bindingsource, data_apapter global objects variables
private DataGridView dataGridView = new DataGridView();
private BindingSource bindingSource = new BindingSource();
private SqlDataAdapter dataAdapter = new SqlDataAdapter();
//class objects
Databases lemars = new Databases();
Databases schuyler = new Databases();
Databases detroitlakeskc = new Databases();
public Form1()
{
InitializeComponent();
}
private void btn_Exit_Click(object sender, EventArgs e)
{
this.Close();
}
private void comboBox_Database_SelectedIndexChanged(object sender, EventArgs e)
{
if (comboBox_Database.SelectedItem.ToString() == "LeMars21St")
{
GetDataToDataGridView();
}
}
private void GetDataToDataGridView()
{
//prgBar_DataGridViewLoading
DatabaseColumns Obj = new DatabaseColumns();
String SqlcmdString = "Select * from dbo.AllInvoicesInReadyStatus";
SqlDataReader reader;
int i = 1;
try
{
using (SqlConnection conn = new SqlConnection(lemars._LeMarsConnectionString))
{
reader = null;
SqlCommand Sqlcmd = new SqlCommand(SqlcmdString, conn);
conn.Open();
reader = Sqlcmd.ExecuteReader();
if (reader.HasRows)
{
try
{
while (reader.Read())
{
Obj.Invoice = reader["invoice"].ToString();
Obj.Shipment = reader["shipment"].ToString();
Obj.Project = reader["Project"].ToString();
Obj.InvoiceDateTB = Convert.ToDateTime(reader["invoiceDateTB"]);
Obj.CreatedDate = Convert.ToDateTime(reader["CreatedDate"]);
Obj.TypeName = reader["typeName"].ToString();
Obj.ExportedDate = Convert.ToDateTime(reader["exportedDate"]);
Obj.StatusName = reader["statusName"].ToString();
Obj.Total = Convert.ToDecimal(reader["total"]);
Obj.ImportStatus = reader["import_status"].ToString();
//DateTime dateFacturation;
int colIndex = reader.GetOrdinal("Time_Completed");
if (!reader.IsDBNull(colIndex))
Obj.TimeCompleted = reader.GetDateTime(colIndex);
Obj.ErrorDescription = reader["ERROR_DESCRIPTION"].ToString();
//bindingSource.DataSource = reader;
DataTable dt = new DataTable();
dt.Load(reader);
dataGridView.DataSource = dt;
i++;
}
}
finally
{
reader.Close();
}
conn.Close();
}
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
}
}

DataTable.Load method automatically closes currently running DataReader instance, hence it will fail at the next iteration (the exception clearly said that the DataReader is already closed).
To fix this issue, call DataTable.Load immediately after ExecuteReader (i.e. after checking by HasRows) and you can iterate DataTable contents from that, as given in example below:
using (SqlConnection conn = new SqlConnection(lemars._LeMarsConnectionString))
{
reader = null;
SqlCommand Sqlcmd = new SqlCommand(SqlcmdString, conn);
conn.Open();
reader = Sqlcmd.ExecuteReader();
if (reader.HasRows)
{
try
{
DataTable dt = new DataTable();
dt.Load(reader);
for (int i = 0; i < dt.Rows.Count; i++)
{
Obj.Invoice = dt.Rows[i]["invoice"].ToString();
Obj.Shipment = dt.Rows[i]["shipment"].ToString();
Obj.Project = dt.Rows[i]["Project"].ToString();
// other stuff
}
dataGridView.DataSource = dt;
}
finally
{
conn.Close();
}
}
}
Update 1:
Since one of your datetime column may contain DBNull.Value, you can check using either Convert.IsDBNull:
for (int i = 0; i < dt.Rows.Count; i++)
{
if (!Convert.IsDBNull(dt.Rows[i]["Time_Completed"]))
{
Obj.TimeCompleted = Convert.ToDateTime(dt.Rows[i]["Time_Completed"]);
}
}
Or with is operator with DBNull:
for (int i = 0; i < dt.Rows.Count; i++)
{
if (!(dt.Rows[i]["Time_Completed"] is DBNull))
{
Obj.TimeCompleted = Convert.ToDateTime(dt.Rows[i]["Time_Completed"]);
}
}
Alternatively you can use ternary operator and set DateTime.MinValue if the column has null value.
Related issues:
Error: Invalid attempt to call Read when reader is closed after the while loop?
C# - Invalid attempt to call Read when reader is closed

Firebird dataReader

I would like to see all of the data with column names in my logfile.
private static void ExecuteSQL()
{
string conn = "User ID=SYSDBA;Password=masterkey;Database=XX.18.137.XXX:C:/ER.TDB;DataSource==XX.18.137.XXX;Charset=NONE;";
FbConnection myConnection = new FbConnection(conn);
FbDataReader myReader = null;
string sql = "SELECT * FROM RDB$RELATIONS";
FbCommand myCommand = new FbCommand(sql, myConnection);
try
{
myConnection.Open();
myCommand.CommandTimeout = 0;
myReader = myCommand.ExecuteReader();
while (myReader.Read())
{
// Log.WriteLog(myReader["rdb$relation_name"].ToString());
}
myConnection.Close();
}
catch (Exception e)
{
Log.WriteLog(e.ToString());
}
}
Right now it's only showing me the rdb$relation_name column.
I want to check the different tables for which I don't have the column's name.

All you need to do is iterate over all fields printing their names before iterating the results:
private static void ExecuteSQL()
{
string conn = "User ID=SYSDBA;Password=masterkey;Database=XX.18.137.XXX:C:/ER.TDB;DataSource==XX.18.137.XXX;Charset=NONE;";
FbConnection myConnection = new FbConnection(conn);
FbDataReader myReader = null;
string sql = "SELECT * FROM RDB$RELATIONS";
FbCommand myCommand = new FbCommand(sql, myConnection);
try
{
myConnection.Open();
myCommand.CommandTimeout = 0;
myReader = myCommand.ExecuteReader();
// 1. print all field names
for (int i = 0; i < myReader.FieldCount; i++)
{
Log.WriteLog(myReader.GetName(i));
}
// 2. print each record
while (myReader.Read())
{
// 3. for each record, print every field value
for (int i = 0; i < myReader.FieldCount; i++)
{
Log.WriteLog(myReader[i].ToString());
}
}
myConnection.Close();
}
catch (Exception e)
{
Log.WriteLog(e.ToString());
}
}
I am pretty sure, that this will give ugly output as it prints every output to a new line. You should be able to change this to print the fields and each record in rows.

public static List<string> GetColumnNames(string queryString)
{
string result = string.Empty;
List<string> listOfColumns = new List<string>();
try
{
using (FbConnection conn = new FbConnection(connString))
{
conn.Open();
using (FbCommand cmd = new FbCommand(queryString, conn))
{
// Call Read before accessing data.
FbDataReader reader = cmd.ExecuteReader();
if (reader.FieldCount > 0)
{
for (int i = 0; i < reader.FieldCount; i++)
{
listOfColumns.Add(reader.GetName(i));
}
}
}
}
}
catch (Exception e)
{
BinwatchLogging.Log(e);
}
return listOfColumns;
// return result;
}
where querystring is your query (eg: select * from yourtablename) and connstring is your firebird connectionstring

ASP.Net C# - Remove controls dynamically

I dynamically create a RadioButtonList or a CheckBoxList depending on a condition within a Button_Click event (which works).
protected void btnGetQuestion_Click(object sender, EventArgs e)
{
string connStr = ConfigurationManager.ConnectionStrings["myConnectionString"].ConnectionString;
MySqlConnection conn = new MySqlConnection(connStr);
MySqlDataReader reader;
List<string> listOfAnswerIDs = new List<string>();
List<string> listOfAnswers = new List<string>();
List<string> listOfCorrectAnswerIDs = new List<string>();
int questionCounter = 0;
//get questionIDs and store in ViewState["listOfQuestionIDs"]
getListOfQuestionIDs();
try
{
conn.Open();
string cmdText = "SELECT * FROM questions_m WHERE question_id=#QuestionID";
MySqlCommand cmd = new MySqlCommand(cmdText, conn);
cmd.Parameters.Add("#QuestionID", MySqlDbType.Int32);
cmd.Parameters["#QuestionID"].Value = listOfQuestionIDs[questionCounter];
reader = cmd.ExecuteReader();
if (reader.Read())
{
lblQuestion.Text = reader["question"].ToString();
if (reader["type"].ToString().Equals("C"))
{
CheckBoxList cblAnswers = new CheckBoxList();
cblAnswers.ID = "cblAnswers";
Page.Form.Controls.Add(cblAnswers);
}
else if (reader["type"].ToString().Equals("R"))
{
RadioButtonList rblAnswers = new RadioButtonList();
rblAnswers.ID = "rblAnswers";
Page.Form.Controls.Add(rblAnswers);
}
questionCounter += 1;
ViewState["questionCounter"] = questionCounter;
ViewState["QuestionID"] = Convert.ToInt32(reader["question_id"]);
reader.Close();
string cmdText2 = "SELECT * FROM answers WHERE question_id=#QuestionID";
MySqlCommand cmdAnswers = new MySqlCommand(cmdText2, conn);
cmdAnswers.Parameters.Add("#QuestionID", MySqlDbType.Int32);
cmdAnswers.Parameters["#QuestionID"].Value = ViewState["QuestionID"];
reader = cmdAnswers.ExecuteReader();
while (reader.Read())
{
listOfAnswerIDs.Add(reader["answer_id"].ToString());
listOfAnswers.Add(reader["answer"].ToString());
}
reader.Close();
populateAnswers(listOfAnswers, listOfAnswerIDs);
}
reader.Close();
}
catch
{
lblError.Text = "Database connection error - failed to read records.";
}
finally
{
conn.Close();
}
}
I want to create a method that I can run in another button click event (btnNext_Click) that will remove the RadioButtonList or CheckBoxList if one exists.
I've tried the following but it doesn't seem to work:
protected void clearAnswers()
{
if (((CheckBoxList)this.FindControl("cblAnswers")) != null)
{
Page.Form.Controls.Remove(this.FindControl("cblAnswers"));
}
if (((RadioButtonList)this.FindControl("rblAnswers")) != null)
{
Page.Form.Controls.Remove(this.FindControl("rblAnswers"));
}
}
UPDATE:
I think the issue I had occured with the repopulation of the RadioButtonList/CheckBoxList. If I cleared each item before repopulating them, that resolved my problem.
if (((CheckBoxList)this.FindControl("cblAnswers")) != null)
{
((CheckBoxList)this.FindControl("cblAnswers")).Items.Clear();
foreach (int num in numbers)
{
((CheckBoxList)this.FindControl("cblAnswers")).Items.Add(ans[num - 1]);
}
}
if (((RadioButtonList)this.FindControl("rblAnswers")) != null)
{
((RadioButtonList)this.FindControl("rblAnswers")).Items.Clear();
foreach (int num in numbers)
{
((RadioButtonList)this.FindControl("rblAnswers")).Items.Add(ans[num - 1]);
}
}

Try this:
protected void clearAnswers()
{
CheckBoxList cblAnswers = (CheckBoxList)this.FindControl("cblAnswers");
RadioButtonList rblAnswers = (RadioButtonList)this.FindControl("rblAnswers");
if (cblAnswers != null)
{
Page.Form.Controls.Remove(cblAnswers);
}
if (rblAnswers != null)
{
Page.Form.Controls.Remove(rblAnswers);
}
}