private void button1_Click(object sender, EventArgs e)
{
int f = 1;
SqlConnection con = new SqlConnection(#"Data Source = (LocalDB)\MSSQLLocalDB; database = 'C:\Users\Emil Sharier\Documents\testDB.mdf'; Integrated Security = True; Connect Timeout = 30");
SqlCommand cmd = new SqlCommand();
cmd.Connection = con;
con.Open();
int bal = 0;
string cmdstr = "select * from users where userid='"+ Form1.userid+"';";
cmd.CommandText = cmdstr;
SqlDataReader dr = cmd.ExecuteReader();
if (dr.Read())
bal = int.Parse(dr[2].ToString());
int draw = int.Parse(textBox1.Text);
if(draw > bal)
{
MessageBox.Show("Insufficient balance!");
return;
}
else
{
bal -= draw;
cmdstr = "update users set balance='"+bal.ToString()+"' where userid='"+ Form1.userid + "';";
SqlDataAdapter da = new SqlDataAdapter();
da.UpdateCommand = con.CreateCommand();
da.UpdateCommand.CommandText = cmdstr;
try
{
da.UpdateCommand.ExecuteNonQuery();
}
catch(Exception ex)
{
f = 0;
}
if (f == 1)
MessageBox.Show("Money withdrawn succesfully!");
else
MessageBox.Show("Enter correct amount!");
}
con.Close();
}
I am getting an "InvalidOperationException" while executing this program. I am not sure what the error is. Please help.
da.UpdateCommand.ExecuteNonQuery() is not getting executed
......
var sqlcmd = new SqlCommand(cmdstr, con);
.....
try
{
sqlcmd.ExecuteNonQuery();
....
Don't use adapter.
And yes. Faster of all try to close connection and open new one for update operation.
Related
I am having a problem with the following code:
namespace Elite_Shop
{
public partial class Bill : Form
{
int j;
int total = 0;
SqlConnection sqlcon = new SqlConnection(#"Data Source=HP\SQLEXPRESS;Initial Catalog=EliteShop;Integrated Security=True ");
public Bill()
{
InitializeComponent();
}
public void get_value(int i)
{
j = i;
}
private void Bill_Load(object sender, EventArgs e)
{
if (sqlcon.State == ConnectionState.Open)
{
sqlcon.Close();
}
sqlcon.Open();
DataSet1 ds = new DataSet1();
SqlCommand cmd = new SqlCommand();
cmd.CommandType = CommandType.Text;
cmd.CommandText = "Select * from Salesman_Table Where SMID="+j+"";
cmd.ExecuteNonQuery();
DataTable dt = new DataTable();
SqlDataAdapter da = new SqlDataAdapter(cmd);
da.Fill(ds.DataTable1);
SqlCommand cmd2 = new SqlCommand();
cmd2.CommandType = CommandType.Text;
cmd2.CommandText = "Select * from Sale_Table Where OrderID=" + j + "";
cmd2.ExecuteNonQuery();
DataTable dt2 = new DataTable();
SqlDataAdapter da2 = new SqlDataAdapter(cmd2);
da2.Fill(ds.DataTable2);
da2.Fill(dt2);
foreach (DataRow dr2 in dt2.Rows)
{
total = total + Convert.ToInt32(dr2["Sub Total"].ToString());
}
SaleReport sr = new SaleReport();
sr.SetDataSource(ds);
sr.SetParameterValue("Grand Total", total.ToString());
crystalReportViewer1.ReportSource = sr;
}
}
}
When executed, the following error message is returned:
ExecuteNonQuery: Connection property has not been initialized.
How do I fix it?
You need to set the Connection property on the SqlCommand:
cmd.Connection = sqlcon;
I have code for deleting a row in C# using a SqlCommand. But I want to delete multiple rows. Can anyone help me with this? I am new to C#.
This is my code - please help. Thank you in advance.
foreach (DataGridViewRow dr in dataGrid1.SelectedRows)
{
SqlConnection con = new SqlConnection();
con.ConnectionString = #"Data Source=DDBULK10\SQLEXPRESS;Initial Catalog=MasterList; Integrated Security = True";
if (dr.Index > 0)
{
int selectedIndex = dataGrid1.SelectedRows[0].Index;
int rowID = int.Parse(dataGrid1[0, selectedIndex].Value.ToString());
string sql = "DELETE FROM ActiveUser WHERE EmpId = #EmpId";
SqlCommand deleteRecord = new SqlCommand();
deleteRecord.Connection = con;
deleteRecord.CommandType = CommandType.Text;
deleteRecord.CommandText = sql;
SqlParameter RowParameter = new SqlParameter();
RowParameter.ParameterName = "#EmpId";
RowParameter.SqlDbType = SqlDbType.Int;
RowParameter.IsNullable = false;
RowParameter.Value = rowID;
deleteRecord.Parameters.Add(RowParameter);
deleteRecord.Connection.Open();
deleteRecord.ExecuteNonQuery();
//deleteRecord.Connection.Close();
MessageBox.Show("Record Successfully Deleted");
SqlDataAdapter sda = new SqlDataAdapter("select * from ActiveUser", con);
DataTable dt = new DataTable();
sda.Fill(dt);
dataGrid1.DataSource = dt;
}
else if (dialogResult == DialogResult.No)
{
this.Refresh();
}
}
You can build a comma separated userid list like -
string strUserIds = string.Empty();
for(int i=0; i<dataGrid.Count;i++)
{
strUserIds = strUserIds +","+ dataGrid.SelectedRows[0].Cells[0].Value;
}
--Remove last unwanted comma from strUserIds
then execute sql query as "DELETE FROM EmployeeTbl WHERE UserID in (" + strUserIds + ")"
This will delete multiple records from table.
Just Make some changes in Your Coding !
Delete All Selected Rows
Run Your select * from ActiveUser
public void deldata()
{
foreach (DataGridViewRow dr in dataGrid1.SelectedRows)
{
SqlConnection con = new SqlConnection();
con.ConnectionString = #"Data Source=DDBULK10\SQLEXPRESS;Initial Catalog=MasterList; Integrated Security = True";
if (dr.Index > 0)
{
int selectedIndex = dataGrid1.SelectedRows[0].Index;
int rowID = int.Parse(dataGrid1[0, selectedIndex].Value.ToString());
string sql = "DELETE FROM ActiveUser WHERE EmpId = #EmpId";
SqlCommand deleteRecord = new SqlCommand();
deleteRecord.Connection = con;
deleteRecord.CommandType = CommandType.Text;
deleteRecord.CommandText = sql;
SqlParameter RowParameter = new SqlParameter();
RowParameter.ParameterName = "#EmpId";
RowParameter.SqlDbType = SqlDbType.Int;
RowParameter.IsNullable = false;
RowParameter.Value = rowID;
deleteRecord.Parameters.Add(RowParameter);
deleteRecord.Connection.Open();
deleteRecord.ExecuteNonQuery();
//deleteRecord.Connection.Close();
MessageBox.Show("Record Successfully Deleted");
}
else if (dialogResult == DialogResult.No)
{
this.Refresh();
}
}
}
public void showdata()
{
SqlDataAdapter sda = new SqlDataAdapter("select * from ActiveUser", con);
DataTable dt = new DataTable();
sda.Fill(dt);
dataGrid1.DataSource = dt;
}
You can use something like this; i didn't test the code but it should work if you create the parameters you need, before running code you have to create a type table, please see the link for details.
using (connection)
{
string sql ="Delete from YourTable t join #yourTypeTable i on t.id = i.Id:";
SqlCommand deleteCommand = new SqlCommand(sql, connection);
SqlParameter tvpParam = deleteCommand.Parameters.AddWithValue("#yourTypeTable", yourIdList);
tvpParam.SqlDbType = SqlDbType.Structured;
tvpParam.TypeName = "dbo.yourTypeTable";
deleteCommand.ExecuteNonQuery();
}
I an trying to do a simple task of reading from one table "tab2" in a database->save to xml and then reload it into table "tab1" both have the same structure, I asked previously and received the following code as an answer.
I am having problems I am now getting the database filed ONCE per item but with a date time stamp I don't think its writing the XML from reading the database properly I am running it twice to get the schema and once for data.
private void button1_Click(object sender, EventArgs e)
{
try
{
string ConnString = (#"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\\temp\\names.accdb;Persist Security Info=False");
using (OleDbConnection Conn = new OleDbConnection(ConnString))
{
//Conn.Close();//severl times connection has been open
Conn.Open();
DataSet ds = new DataSet();
ds.ReadXml(#"c:\\temp\\tab2.xml");
OleDbCommand cmd = new OleDbCommand();
//OleDbCommand cmd1 = new OleDbCommand();
DataTable dtCSV = new DataTable();
dtCSV = ds.Tables[0];
cmd.Connection = Conn;
cmd.CommandType = CommandType.Text;
//cmd.Parameters.Add(new OleDbParameter("#field1", Convert.ToString(dtCSV.Rows[0][0])));// = 1234;
//cmd1.Connection = Conn;
for (int row = 0; row <= dtCSV.Rows.Count - 1; row++)
{
//for (int col = 0; col < dtCSV.Columns.Count - 1; col++)
//{
// //cmd.CommandText = ("INSERT INTO tab1 ( field1, field2) VALUES (dtCSV.Rows ,dtCSV.Columns)");
//}
cmd.Parameters.Clear();
if (dtCSV.Columns.Count > 1)
{
//command.Parameters.Add(new OleDbParameter("#EMPID", Convert.Tostring(empsplitIt[1])));
//cmd.Parameters.Add(dtCSV.Rows[row][0]);
cmd.Parameters.Add(new OleDbParameter("#Field1", Convert.ToString(dtCSV.Rows[row][0])));
cmd.Parameters.Add(new OleDbParameter("#dtCSV", Convert.ToString(dtCSV.Rows[row][1])));
cmd.CommandText = ("INSERT INTO tab1 ( field1, field2) VALUES (? , ?)");
cmd.ExecuteNonQuery();
}
}
//Conn.Close();
}
}
catch (Exception ex)
{
richTextBox1.Text = richTextBox1.Text + "\n Error " + ex + "\n"; ;
}
}
private void button2_Click(object sender, EventArgs e)
{
{
string ConnString = (#"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\\temp\\names.mdb;Persist Security Info=False");
using (OleDbConnection Conn = new OleDbConnection(ConnString))
{
string strSql = "Select * from Table1"; //only launch in main
richTextBox1.Text = richTextBox1.Text + " Querying Launch Parameters";
try
{
OleDbConnection con = new OleDbConnection("Provider = Microsoft.ACE.OLEDB.12.0; Data Source = C:\\temp\\names.mdb; Persist Security Info = False");
OleDbCommand cmd = new OleDbCommand(strSql, con);
con.Open();
cmd.CommandType = CommandType.Text;
OleDbDataAdapter da = new OleDbDataAdapter(cmd);
DataSet ds = new DataSet();
da.Fill(ds, "fname,sname");
// Extract data set to XML file
ds.WriteXml(#"c:\\temp\\tab2.xml", XmlWriteMode.WriteSchema);
ds.WriteXml(#"c:\\temp\\tab2.xml");
}
catch (Exception ex)
{
richTextBox1.Text = richTextBox1.Text + "\n Error " + ex + "\n"; ;
}
}
}
}
}
I find from my code that there is two different connection strings with in it when I putin the corect spelling correcting these it now fails on the line
dtCSV = ds.Tables[0];
with this
Error System.IndexOutOfRangeException: Cannot find table 0.
at System.Data.DataTableCollection.get_Item(Int32 index)
at WindowsFormsApp8.Form1.button1_Click(Object sender, EventArgs e) in
Code:
private void button1_Click(object sender, EventArgs e)
{
try
{
string ConnString = (#"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\\temp\\names.mdb;Persist Security Info=False");
using (OleDbConnection Conn = new OleDbConnection(ConnString))
{
//Conn.Close();//severl times connection has been open
Conn.Open();
DataSet ds = new DataSet();
ds.ReadXml(#"c:\\temp\\tabel2.xml");
OleDbCommand cmd = new OleDbCommand();
//OleDbCommand cmd1 = new OleDbCommand();
DataTable dtCSV = new DataTable("tabel1");
dtCSV = ds.Tables[0];
cmd.Connection = Conn;
cmd.CommandType = CommandType.Text;
//cmd.Parameters.Add(new OleDbParameter("#field1", Convert.ToString(dtCSV.Rows[0][0])));// = 1234;
//cmd1.Connection = Conn;
for (int row = 0; row <= dtCSV.Rows.Count - 1; row++)
{
//for (int col = 0; col < dtCSV.Columns.Count - 1; col++)
//{
// //cmd.CommandText = ("INSERT INTO tab1 ( field1, field2) VALUES (dtCSV.Rows ,dtCSV.Columns)");
//}
cmd.Parameters.Clear();
if (dtCSV.Columns.Count > 1)
{
//command.Parameters.Add(new OleDbParameter("#EMPID", Convert.Tostring(empsplitIt[1])));
//cmd.Parameters.Add(dtCSV.Rows[row][0]);
cmd.Parameters.Add(new OleDbParameter("#field1", Convert.ToString(dtCSV.Rows[row][0])));
cmd.Parameters.Add(new OleDbParameter("#field2", Convert.ToString(dtCSV.Rows[row][1])));
cmd.CommandText = ("INSERT INTO tabel1 ( field1, field2) VALUES (? , ?)");
cmd.ExecuteNonQuery();
}
}
//Conn.Close();
}
}
catch (Exception ex)
{
richTextBox1.Text = richTextBox1.Text + "\n Error " + ex + "\n"; ;
}
}
private void button2_Click(object sender, EventArgs e)
{
{
string ConnString = (#"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\\temp\\names.mdb;Persist Security Info=False");
using (OleDbConnection Conn = new OleDbConnection(ConnString))
{
string strSql = "Select * from tabel2"; //only launch in main
richTextBox1.Text = richTextBox1.Text + " Querying Launch Parameters";
try
{
OleDbConnection con = new OleDbConnection(ConnString);
OleDbCommand cmd = new OleDbCommand(strSql, con);
con.Open();
cmd.CommandType = CommandType.Text;
OleDbDataAdapter da = new OleDbDataAdapter(cmd);
DataSet ds = new DataSet();
da.Fill(ds, "fname,sname");
// Extract data set to XML file
ds.WriteXml(#"c:\\temp\\tabel2.xml", XmlWriteMode.WriteSchema);
ds.WriteXml(#"c:\ \temp\\tabel2.xml");
}
catch (Exception ex)
{
richTextBox1.Text = richTextBox1.Text + "\n Error " + ex + "\n"; ;
}
}
}
}
}
private void bLogIn(object sender, EventArgs e)
{
string logging = "select * from CLIENT where LOGIN='" + this.t_Login.Text + "' and PASSWORD='" + this.t_Password.Text + "' ;";
OracleConnection conn = new OracleConnection("Data Source=XXX/orcl;User Id=XXX;Password=XXX;");
OracleCommand cmd = new OracleCommand();
cmd.CommandText = logging;
cmd.Connection = conn;
try
{
conn.Open();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
int count = 0;
OracleDataReader reader = cmd.ExecuteReader(); // At this line there is the error: Operation is not valid due to the current state of the object
while (reader.Read())
{
count = count + 1;
}
if (count == 1)
{
MessageBox.Show("Welcome");
}
else
{
MessageBox.Show("Wrong Password");
}
conn.Dispose();
}
This is code that was working for MySQL, but after conversion to Oracle it's not working. What am I doing wrong? Where's the difference. It should be so easy as in MySQL, right?
Why "OracleDataReader reader = cmd.ExecuteReader();" causes error: "Operation is not valid due to the current state of the object" ???
You are not assingning the connection to cmd.. try code below
OracleCommand cmd = new OracleCommand();
cmd.connection = conn;
cmd.CommandText = logging;
int count = 0;
OracleDataReader reader = cmd.ExecuteReader();
I retrived values by the use of SqlCommand and SqlReader from column and stored in List<String> and the added to ComboBox(Type:DropDownList) but Eventhough i have deleted Some of this values from database Combobox is still showing it.
I am clearing items befor allocating by
mycombobox.Items.Clear();
It looks as it is not affected by values I retrive every time when the Form gets Loaded.
SqlDataReader rdr1 = null;
SqlConnection con1 = null;
SqlCommand cmd1 = null;
try
{
List<string> namesCollection=new List<string>();
// Open connection to the database
string ConnectionString = #"Data Source=MyPC-PC\SQLEXPRESS;Initial Catalog=DryDB;Integrated Security=True";
con1 = new SqlConnection(ConnectionString);
con1.Open();
cmd1 = new SqlCommand();
cmd1.CommandType = CommandType.Text;
cmd1.CommandText = "SELECT PName from MASTER order by PName";
cmd1.Connection = con1;
rdr1 = cmd1.ExecuteReader();
namesCollection.Add("Select");
if (rdr1.Read()==true)
{
do
{
namesCollection.Add("" + rdr1[0].ToString());
} while (rdr1.Read()) ;
}
else
{
}
foreach(string pname in namesCollection)
cb.Items.Add(pname);
namesCollection.Clear();
cb.SelectedIndex =0;
}
catch (Exception ex) {
MessageBox.Show(ex.Message);
if (rdr1 != null)
rdr1.Close();
if (con1.State == ConnectionState.Open)
con1.Close();
}
Thanks in advance.
Use the DataSource property of the Combobox instead of the adding the items one by one. So your code will be something like the following:
SqlDataReader rdr1 = null;
SqlConnection con1 = null;
SqlCommand cmd1 = null;
try
{
List<string> namesCollection = new List<string>();
// Open connection to the database
string ConnectionString = #"Data Source=MyPC-PC\SQLEXPRESS;Initial Catalog=DryDB;Integrated Security=True";
con1 = new SqlConnection(ConnectionString);
con1.Open();
cmd1 = new SqlCommand();
cmd1.CommandType = CommandType.Text;
cmd1.CommandText = "SELECT PName from MASTER order by PName";
cmd1.Connection = con1;
rdr1 = cmd1.ExecuteReader();
namesCollection.Add("Select");
if (rdr1.Read()==true)
{
do
{
namesCollection.Add("" + rdr1[0].ToString());
} while (rdr1.Read()) ;
}
else
{
}
//Replace this part...
//foreach(string pname in namesCollection)
//cb.Items.Add(pname);
//With this...
cb.DataSource = namesCollection;
cb.SelectedIndex =0;
}
catch (Exception ex) {
MessageBox.Show(ex.Message);
if (rdr1 != null)
rdr1.Close();
if (con1.State == ConnectionState.Open)
con1.Close();
}
There is a similar question here
Hope this helps
Let's say the code to populate the ComboBox is placed in the populate_cb() method
private void populate_cb(){
cb.Items.Clear();
SqlDataReader rdr1 = null;
SqlConnection con1 = null;
SqlCommand cmd1 = null;
try
{
// Open connection to the database
string ConnectionString = #"Data Source=MyPC-PC\SQLEXPRESS;Initial Catalog=DryDB;Integrated Security=True";
con1 = new SqlConnection(ConnectionString);
con1.Open();
cmd1 = new SqlCommand();
cmd1.CommandType = CommandType.Text;
cmd1.CommandText = "SELECT PName from MASTER order by PName";
cmd1.Connection = con1;
rdr1 = cmd1.ExecuteReader();
cb.Items.Add("Select");
while(rdr1.Read())
{
cb.Items.Add(rdr1[0].ToString());
}
cb.SelectedIndex =0;
con1.Close();
}
catch(Exception ex){
// handle exception
}
}//end of populate_cb()
Call populate_cb() method form form_load() and
Call from the place after the deletion process
You need to make sure your deletion process really deletes the records from database!