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delete and update the selected row

executenonquery is my problem, this code works on other button in different datagridview
here's my code at delete button
private void button4_Click_2(object sender, EventArgs e)
{
SqlConnection con = new SqlConnection(#"Data Source=XXYZZ\SQLEXPRESS;Initial Catalog=rick_inventiory;Integrated Security=True");
SqlCommand cmd = con.CreateCommand();
cmd.CommandType = CommandType.Text;
cmd.CommandText = "Delete from tbl_Orders where CustomersID2 = '" + dataGridView5.SelectedRows[0].Cells[0].Value.ToString() + "'";
con.Open();
cmd.Parameters.AddWithValue("#CustomerID2", txtCustomerID2.Text);
cmd.ExecuteNonQuery();
con.Close();
disp_data();
MessageBox.Show("Deleted Successfully");
}
the update code still execute sa code but did not update it
and heres my code for Update button
SqlConnection con = new SqlConnection(#"Data Source=XXYZZ\SQLEXPRESS;Initial Catalog=rick_inventiory;Integrated Security=True");
con.Open();
SqlCommand cmd = con.CreateCommand();
cmd.CommandType = CommandType.Text;
cmd.CommandText = "Update tbl_Products SET ProductName='" + txtProName.Text +
"',Stocks='" + txtStocks.Text + "',Price='" + txtPrice.Text + "',Description='" +
txtDesc.Text + "',CategoryName='" + txtCat.Text + "' where ProductID ='" + txtProID.Text + "';";
cmd.ExecuteNonQuery();
SqlDataAdapter da = new SqlDataAdapter("Select * from tbl_Products", con);
DataTable dt = new DataTable();
da.Fill(dt);
dataGridView1.DataSource = dt;
MessageBox.Show("Successfuly Updated");
con.close();

In update there is a syntax problem remove inner side semi colon of update query
While in delete you want to change the line
from
cmd.Parameters.AddWithValue("#CustomerID2", txtCustomerID2.Text);
to
cmd.Parameters.AddWithValue("#CustomerID2", '" + dataGridView5.SelectedRows[0].Cells[0].Value.ToString() + "');

"ExecuteReader:Connection Property has not been initialized."

private void btnSave_Click(object sender, EventArgs e)
{
try
{
con = new SqlConnection("Data Source = LENOVO; Initial Catalog = MainData; Integrated Security = True");
con.Open();
string CheckID = "select StaffID from PersonsData where StaffID='" + txtStaffID.Text + "'";
cm = new SqlCommand(CheckID);
SqlDataReader rdr = null;
rdr = cm.ExecuteReader();
if (rdr.Read())
{
MessageBox.Show("Company Name Already Exists", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
txtStaffID.Text = "";
txtStaffID.Focus();
}
else
{
byte[] img = null;
FileStream fs = new FileStream(imgLoc, FileMode.Open, FileAccess.Read);
BinaryReader br = new BinaryReader(fs);
img = br.ReadBytes((int)fs.Length);
string Query = "insert into PersonsData (StaffID, FullName, Email, Address, Picture) values('" + this.txtStaffID.Text + "','" + this.txtFullname.Text + "','" + this.txtEmail.Text + "','" + this.txtAddress.Text + "',#img)";
if (con.State != ConnectionState.Open)
con.Open();
cm = new SqlCommand(Query, con);
cm.Parameters.Add(new SqlParameter("#img", img));
int x = cm.ExecuteNonQuery();
con.Close();
MessageBox.Show(x.ToString() + "Successfully Saved!");
}
}
catch (Exception ex)
{
con.Close();
MessageBox.Show(ex.Message);
}
}
This is my code i don't understand why I'm getting this error:
ExecuteReader:Connection Property has not been initialized.
I'm making a save button where the Staffid will be checked first if already.

Before executing the command, you need to say which connection is to be used. In your case, it is:
cm.Connection = con;
Take a note that, include this line of code after opening the connection and after creating the instance of SqlCommand.

con = new SqlConnection("Data Source = LENOVO; Initial Catalog = MainData; Integrated Security = True");
con.Open();
string CheckID = "select StaffID from PersonsData where StaffID='" + txtStaffID.Text + "'";
cm = new SqlCommand(CheckID);
cm.Connection = con; //Assign connection to command
You didn't assign connection to SqlCommand used in the reader

The error message is clear enough, You have to assign the connection for the Command, either through assignement or through the constructor, That is:
cm = new SqlCommand(CheckID);
cm.Connection = con; // Should be added
SqlDataReader rdr = cm.ExecuteReader();
Or else you can use the constructor to initialize the command like this:
cm = new SqlCommand(CheckID,con);
Hope that you are aware of these things since you ware used it correctly in the else part of the given snippet

Make sure that you assign the SqlConnection to your Command-Object. You can do this via Constructor or Property:
con = new SqlConnection(//Your Connectionstring)
//assign via Constructor
cm = new SqlCommand(CheckID, con);
//or via Property
cm.Connection = con;
SqlDataReader rdr = null;
rdr = cm.ExecuteReader();
Further I would recommend you to use a using-block to make sure that the Command and Connection gets destroyed after using it.
using (var con = new SqlConnection())
{
using (var cm = new SqlCommand())
{
}
}

Populating SQL Server Datatable

My program will not update my SQL Server database after executing. When I run my program my DataGridView updates when I insert my information, but it will not update itself in the dataTable.
private void button1_Click(object sender, EventArgs e)
{
string query = "INSERT INTO dbo.dataTable(Id,Name,Age) VALUES('" + idTextBox.Text + "','" + nameTextBox.Text + "','" + ageTextBox.Text + "')";
SqlConnection conn = new SqlConnection(#"Data Source=(LocalDB)\v11.0;AttachDbFilename=|DataDirectory|\employee.mdf;Integrated Security=True;Connect Timeout=30");
SqlCommand cmd;
conn.Open();
cmd = new SqlCommand(query, conn);
cmd.ExecuteNonQuery();
this.dataTableTableAdapter.Fill(this.employeeDataSet1.dataTable);
conn.Close();
SqlDataAdapter adapt = new SqlDataAdapter(cmd);
DataTable data = new DataTable();
conn.Open();
adapt.Update(data);
conn.Close();
dataTableDataGridView.DataSource = data;
}

If you created your DataGridView using the designer which added a dataset, bindingsource, and tableadapter, then your DataGridView should be configured correctly out of the box. Try commented out these lines:
//SqlDataAdapter adapt = new SqlDataAdapter(cmd);
//DataTable data = new DataTable();
//conn.Open();
//adapt.Update(data);
//conn.Close();
//dataGridView1.DataSource = data;
I replicated your button_click code and it works locally for me using Sql Express.

Based on your comment i assume the cause is the missing conversion. Using Int32.TryParse you can convert the string to int. Be aware that the ' have to go as well
int id, age;
bool idIsInt = false, ageIsInt = false;
idIsInt = Int32.TryParse(idTextBox.Text, out id);
ageIsInt = Int32.TryParse(ageTextBox.Text, out age);
if(idIsInt && ageIsInt)
{
string query = "INSERT INTO dbo.dataTable(Id,Name,Age) VALUES("
+ id + ",'" + nameTextBox.Text + "',"
+ age + ")";
SqlConnection conn =
new SqlConnection(#"Data Source(LocalDB)\v11.0;AttachDbFilename=|DataDirectory|\employee.mdf
;Integrated Security=True;Connect Timeout=30");
SqlCommand cmd;
conn.Open();
cmd = new SqlCommand(query, conn);
cmd.ExecuteNonQuery();
}

Can you help me to show datagridview and Refresh after update?

This is my code and error message when you running say:
An unhandled exception of type System.Data.SqlClient.SqlException
occurred in System.Data.dll
on this da.fill(dt);
SqlConnection con = new SqlConnection("Data Source=ANTONIANGGA-PC\\SQLEXPRESS;Initial Catalog=FullandStarving;Integrated Security=True");
SqlCommand cmd;
SqlDataAdapter da;
DataTable dt = new DataTable();
public FormProduksi()
{
InitializeComponent();
showgridview();
}
private void showgridview()
{
con.Open();
dt.Clear();
cmd = new SqlCommand("SELECT * FROM Produksi", con);
//cmd.CommandType = CommandType.StoredProcedure; done :D
da = new SqlDataAdapter(cmd);
da.Fill(dt);
dataGridView1.DataSource = dt;
con.Close();
}
private void button2_Click(object sender, EventArgs e)
{
//Datetimepicker to Database
string dProduksi = DateTime.Parse(dtmProduksi.Text).ToString("yyyy-MM-dd");
try{
con.Open();
cmd = new SqlCommand("insert into Produksi (IDProduksi,IDPhoto,TanggalProduksi,NamaKaryawan,KeteranganPhoto) Values('" + txtIdpro.Text + "','" + txtIdPhoto.Text + "','" + dProduksi + "','" + txtNamaKaryawan.Text + "','" + rxtKtrphoto.Text + "')", con);
cmd.ExecuteNonQuery();
MessageBox.Show("Update telah di jalankan");
showgridview();
clear();
con.Close();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
that update successfully but cant refresh, so i do quit that form and open can see it

You are closing the connection
con.Close();
and then using
da.Fill(dt);
Just swap this lines:
showgridview();
con.Close();
For example with DbDataAdapter.Fill:
Notes:
1
Yoy should use parametrized queries so you avoid SQL Injection attacks:
var cmd = new SqlCommand("SELECT EmpName FROM Employee WHERE EmpID = #id", con);
cmd.Parameters.AddWithValue("#id", id.Text);
2
Wrap SqlConnection and SqlCommand into using so any resources used by those would disposed:
string position;
using (SqlConnection con = new SqlConnection("server=free-pc\\FATMAH; Integrated Security=True; database=Workflow; "))
{
con.Open();
using (var cmd = new SqlCommand("SELECT EmpName FROM Employee WHERE EmpID = #id", con))
{
cmd.Parameters.AddWithValue("#id", id.Text);
var name = cmd.ExecuteScalar();
if (name != null)
{
position = name.ToString();
Response.Write("User Registration successful");
}
else
{
Console.WriteLine("No Employee found.");
}
}
}
Credit

Just change the showgridview() function as below where connection is opened & closed properly.
Also check your sql query ,provide space and maintain syntax of query :
SELECT * FROM Produksi
Error screenshot clearly depicts that stored procedure with such name don't exist
comment out those lines as code below :
void showgridview()
{
con.Open();
dt.Clear();
cmd = new SqlCommand("SELECT * FROM Produksi", con);
//cmd.CommandType = CommandType.StoredProcedure;
da = new SqlDataAdapter(cmd);
da.Fill(dt);
dataGridView1.DataSource = dt;
con.Close();
}
Then you wont be having connection issues and errors related .
Button Click code change the closing connection as below:
private void button2_Click(object sender, EventArgs e)
{
//Datetimepicker to Database
string dProduksi = DateTime.Parse(dtmProduksi.Text).ToString("yyyy-MM-dd");
try
{
con.Open();
cmd = new SqlCommand("insert into Produksi (IDProduksi,IDPhoto,TanggalProduksi,NamaKaryawan,KeteranganPhoto) Values('" + txtIdpro.Text + "','" + txtIdPhoto.Text + "','" + dProduksi + "','" + txtNamaKaryawan.Text + "','" + rxtKtrphoto.Text + "')", con);
cmd.ExecuteNonQuery();
MessageBox.Show("Update telah di jalankan");
con.Close();
showgridview();
clear();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
Also, for further reading:
parameterized queries vs. SQL injection
Why do we always prefer using parameters in SQL statements?

How to run multiple SQL commands in a single SQL connection?

I am creating a project in which I need to run 2-3 SQL commands in a single SQL connection.
Here is the code I have written:
SqlConnection con = new SqlConnection(#"Data Source=(LocalDB)\v11.0;AttachDbFilename=|DataDirectory|\project.mdf;Integrated Security=True");
con.Open();
SqlCommand cmd = new SqlCommand("select * from " + mytags.Text + " ", con);
SqlDataReader rd = cmd.ExecuteReader();
if (rd.Read())
{
con.Close();
con.Open();
SqlCommand cmd1 = new SqlCommand("insert into " + mytags.Text + " values ('fname.lname#gmail.com','" + TextBox3.Text + "','" + TextBox4.Text + "','" + TextBox5.Text + "','"+mytags.Text+"')", con);
cmd1.ExecuteNonQuery();
label.Visible = true;
label.Text = "Date read and inserted";
}
else
{
con.Close();
con.Open();
SqlCommand cmd2 = new SqlCommand("create table " + mytags.Text + " ( session VARCHAR(MAX) , Price int , Description VARCHAR(MAX), Date VARCHAR(20),tag VARCHAR(10))", con);
cmd2.ExecuteNonQuery();
con.Close();
con.Open();
SqlCommand cmd3 = new SqlCommand("insert into " + mytags.Text + " values ('" + Session + "','" + TextBox3.Text + "','" + TextBox4.Text + "','" + TextBox5.Text + "','" + mytags.Text + "')", con);
cmd3.ExecuteNonQuery();
label.Visible = true;
label.Text = "tabel created";
con.Close();
}
I have tried to remove the error and I got that the connection is not going to else condition. Please review the code and suggest if there is any mistake or any other solution for this.

Just change the SqlCommand.CommandText instead of creating a new SqlCommand every time. There is no need to close and reopen the connection.
// Create the first command and execute
var command = new SqlCommand("<SQL Command>", myConnection);
var reader = command.ExecuteReader();
// Change the SQL Command and execute
command.CommandText = "<New SQL Command>";
command.ExecuteNonQuery();

The following should work. Keep single connection open all time, and just create new commands and execute them.
using (SqlConnection connection = new SqlConnection(connectionString))
{
connection.Open();
using (SqlCommand command1 = new SqlCommand(commandText1, connection))
{
}
using (SqlCommand command2 = new SqlCommand(commandText2, connection))
{
}
// etc
}

Just enable this property in your connection string:
sqb.MultipleActiveResultSets = true;
This property allows one open connection for multiple datareaders.

I have not tested , but what the main idea is: put semicolon on each query.
SqlConnection connection = new SqlConnection();
SqlCommand command = new SqlCommand();
connection.ConnectionString = connectionString; // put your connection string
command.CommandText = #"
update table
set somecol = somevalue;
insert into someTable values(1,'test');";
command.CommandType = CommandType.Text;
command.Connection = connection;
try
{
connection.Open();
}
finally
{
command.Dispose();
connection.Dispose();
}
Update:
you can follow
Is it possible to have multiple SQL instructions in a ADO.NET Command.CommandText property? too

This is likely to be attacked via SQL injection by the way. It'd be worth while reading up on that and adjusting your queries accordingly.
Maybe look at even creating a stored proc for this and using something like sp_executesql which can provide some protection against this when dynamic sql is a requirement (ie. unknown table names etc). For more info, check out this link.

No one has mentioned this, but you can also separate your commands using a ; semicolon in the same CommandText:
using (SqlConnection conn = new SqlConnection(connString))
{
using (SqlCommand comm = new SqlCommand())
{
comm.Connection = conn;
comm.CommandText = #"update table ... where myparam=#myparam1 ; " +
"update table ... where myparam=#myparam2 ";
comm.Parameters.AddWithValue("#myparam1", myparam1);
comm.Parameters.AddWithValue("#myparam2", myparam2);
conn.Open();
comm.ExecuteNonQuery();
}
}

Multiple Non-query example if anyone is interested.
using (OdbcConnection DbConnection = new OdbcConnection("ConnectionString"))
{
DbConnection.Open();
using (OdbcCommand DbCommand = DbConnection.CreateCommand())
{
DbCommand.CommandText = "INSERT...";
DbCommand.Parameters.Add("#Name", OdbcType.Text, 20).Value = "name";
DbCommand.ExecuteNonQuery();
DbCommand.Parameters.Clear();
DbCommand.Parameters.Add("#Name", OdbcType.Text, 20).Value = "name2";
DbCommand.ExecuteNonQuery();
}
}

Here you can find Postgre example, this code run multiple sql commands (update 2 columns) within single SQL connection
public static class SQLTest
{
public static void NpgsqlCommand()
{
using (NpgsqlConnection connection = new NpgsqlConnection("Server = ; Port = ; User Id = ; " + "Password = ; Database = ;"))
{
NpgsqlCommand command1 = new NpgsqlCommand("update xy set xw = 'a' WHERE aa='bb'", connection);
NpgsqlCommand command2 = new NpgsqlCommand("update xy set xw = 'b' where bb = 'cc'", connection);
command1.Connection.Open();
command1.ExecuteNonQuery();
command2.ExecuteNonQuery();
command2.Connection.Close();
}
}
}

using (var connection = new SqlConnection("Enter Your Connection String"))
{
connection.Open();
using (var command = connection.CreateCommand())
{
command.CommandText = "Enter the First Command Here";
command.ExecuteNonQuery();
command.CommandText = "Enter Second Comand Here";
command.ExecuteNonQuery();
//Similarly You can Add Multiple
}
}
It worked for me.