Connection property has not been initialized

Connection property has not been initialized - Npgsql C#

-1

I am trying to connect to my postgres database but im getting stuck with Connection property has not been initialized.

I am using a class for open connection

 class DBConnection

        {

            public static NpgsqlConnection conn = null;



            public void Connection_open()

            {

                string connstring = String.Format("Host=localhost;Database=Dokument_API;Username=postgres;Password=******");

                var conn = new NpgsqlConnection(connstring);

                conn.Open();

            }

            public void Connection_close()

            {

                conn.Close();

            }

        }

In form I have this code

private void button1_Click(object sender, EventArgs e)

        {

            //Open connection from class

            DBConnection NewConnection = new DBConnection();

            NewConnection.Connection_open();



            NpgsqlCommand cmd = new NpgsqlCommand("INSERT INTO anrop (exempelanrop,beskrivning,exempelsvar) VALUES ('" + exempelanrop_text.Text + "','" + beskrivning_text.Text + "','" + exempelsvar_text.Text + "')", DBConnection.conn);

            cmd.ExecuteNonQuery();

            MessageBox.Show("Uppgifter sparade");

        }

I get stuck on cmd.ExecuteNonQuery. Why??

asked Nov 13 '18 at 15:12

Daniel Strömberg

2

DBConnection is a bug. You shouldn't have a global connection. A connection should be opened right before it's used and closed as soon as possible. Locks taken while executing queries remain until a connection is closed. This means they end up blocking other connections.

– Panagiotis Kanavos
Nov 13 '18 at 15:16

Everytime you are opening the connection, where is your connection closing also you have used var conn which will neglect the static conn

– Hassaan
Nov 13 '18 at 15:18

If you want a generic, reusable DbConnection abstraction just use the classes already provided by ADO.NET. All ADO.NET provider classes inherit from abstract classes like DbConnection, DbCommand, DbDataReader

– Panagiotis Kanavos
Nov 13 '18 at 15:18

If you worry that opening and closing a connection is costly, don't. Most ADO.NET providers implement connection pooling. When .Dispose() or .Close() is called on a connection, it's reset and put in a connection pool, ready for reuse.

– Panagiotis Kanavos
Nov 13 '18 at 15:19

add a comment |

-1

I am trying to connect to my postgres database but im getting stuck with Connection property has not been initialized.

I am using a class for open connection

 class DBConnection

        {

            public static NpgsqlConnection conn = null;



            public void Connection_open()

            {

                string connstring = String.Format("Host=localhost;Database=Dokument_API;Username=postgres;Password=******");

                var conn = new NpgsqlConnection(connstring);

                conn.Open();

            }

            public void Connection_close()

            {

                conn.Close();

            }

        }

In form I have this code

private void button1_Click(object sender, EventArgs e)

        {

            //Open connection from class

            DBConnection NewConnection = new DBConnection();

            NewConnection.Connection_open();



            NpgsqlCommand cmd = new NpgsqlCommand("INSERT INTO anrop (exempelanrop,beskrivning,exempelsvar) VALUES ('" + exempelanrop_text.Text + "','" + beskrivning_text.Text + "','" + exempelsvar_text.Text + "')", DBConnection.conn);

            cmd.ExecuteNonQuery();

            MessageBox.Show("Uppgifter sparade");

        }

I get stuck on cmd.ExecuteNonQuery. Why??

asked Nov 13 '18 at 15:12

Daniel Strömberg

2

DBConnection is a bug. You shouldn't have a global connection. A connection should be opened right before it's used and closed as soon as possible. Locks taken while executing queries remain until a connection is closed. This means they end up blocking other connections.

– Panagiotis Kanavos
Nov 13 '18 at 15:16

Everytime you are opening the connection, where is your connection closing also you have used var conn which will neglect the static conn

– Hassaan
Nov 13 '18 at 15:18

If you want a generic, reusable DbConnection abstraction just use the classes already provided by ADO.NET. All ADO.NET provider classes inherit from abstract classes like DbConnection, DbCommand, DbDataReader

– Panagiotis Kanavos
Nov 13 '18 at 15:18

If you worry that opening and closing a connection is costly, don't. Most ADO.NET providers implement connection pooling. When .Dispose() or .Close() is called on a connection, it's reset and put in a connection pool, ready for reuse.

– Panagiotis Kanavos
Nov 13 '18 at 15:19

add a comment |

-1

I am trying to connect to my postgres database but im getting stuck with Connection property has not been initialized.

I am using a class for open connection

 class DBConnection

        {

            public static NpgsqlConnection conn = null;



            public void Connection_open()

            {

                string connstring = String.Format("Host=localhost;Database=Dokument_API;Username=postgres;Password=******");

                var conn = new NpgsqlConnection(connstring);

                conn.Open();

            }

            public void Connection_close()

            {

                conn.Close();

            }

        }

In form I have this code

private void button1_Click(object sender, EventArgs e)

        {

            //Open connection from class

            DBConnection NewConnection = new DBConnection();

            NewConnection.Connection_open();



            NpgsqlCommand cmd = new NpgsqlCommand("INSERT INTO anrop (exempelanrop,beskrivning,exempelsvar) VALUES ('" + exempelanrop_text.Text + "','" + beskrivning_text.Text + "','" + exempelsvar_text.Text + "')", DBConnection.conn);

            cmd.ExecuteNonQuery();

            MessageBox.Show("Uppgifter sparade");

        }

I get stuck on cmd.ExecuteNonQuery. Why??

asked Nov 13 '18 at 15:12

Daniel Strömberg

I am trying to connect to my postgres database but im getting stuck with Connection property has not been initialized.

I am using a class for open connection

 class DBConnection

        {

            public static NpgsqlConnection conn = null;



            public void Connection_open()

            {

                string connstring = String.Format("Host=localhost;Database=Dokument_API;Username=postgres;Password=******");

                var conn = new NpgsqlConnection(connstring);

                conn.Open();

            }

            public void Connection_close()

            {

                conn.Close();

            }

        }

In form I have this code

private void button1_Click(object sender, EventArgs e)

        {

            //Open connection from class

            DBConnection NewConnection = new DBConnection();

            NewConnection.Connection_open();



            NpgsqlCommand cmd = new NpgsqlCommand("INSERT INTO anrop (exempelanrop,beskrivning,exempelsvar) VALUES ('" + exempelanrop_text.Text + "','" + beskrivning_text.Text + "','" + exempelsvar_text.Text + "')", DBConnection.conn);

            cmd.ExecuteNonQuery();

            MessageBox.Show("Uppgifter sparade");

        }

I get stuck on cmd.ExecuteNonQuery. Why??

c# npgsql

asked Nov 13 '18 at 15:12

Daniel Strömberg

asked Nov 13 '18 at 15:12

Daniel Strömberg

asked Nov 13 '18 at 15:12

Daniel Strömberg

asked Nov 13 '18 at 15:12

Daniel Strömberg

asked Nov 13 '18 at 15:12

Daniel Strömberg

2

DBConnection is a bug. You shouldn't have a global connection. A connection should be opened right before it's used and closed as soon as possible. Locks taken while executing queries remain until a connection is closed. This means they end up blocking other connections.

– Panagiotis Kanavos
Nov 13 '18 at 15:16

Everytime you are opening the connection, where is your connection closing also you have used var conn which will neglect the static conn

– Hassaan
Nov 13 '18 at 15:18

If you want a generic, reusable DbConnection abstraction just use the classes already provided by ADO.NET. All ADO.NET provider classes inherit from abstract classes like DbConnection, DbCommand, DbDataReader

– Panagiotis Kanavos
Nov 13 '18 at 15:18

If you worry that opening and closing a connection is costly, don't. Most ADO.NET providers implement connection pooling. When .Dispose() or .Close() is called on a connection, it's reset and put in a connection pool, ready for reuse.

– Panagiotis Kanavos
Nov 13 '18 at 15:19

add a comment |

2

DBConnection is a bug. You shouldn't have a global connection. A connection should be opened right before it's used and closed as soon as possible. Locks taken while executing queries remain until a connection is closed. This means they end up blocking other connections.

– Panagiotis Kanavos
Nov 13 '18 at 15:16

Everytime you are opening the connection, where is your connection closing also you have used var conn which will neglect the static conn

– Hassaan
Nov 13 '18 at 15:18

If you want a generic, reusable DbConnection abstraction just use the classes already provided by ADO.NET. All ADO.NET provider classes inherit from abstract classes like DbConnection, DbCommand, DbDataReader

– Panagiotis Kanavos
Nov 13 '18 at 15:18

If you worry that opening and closing a connection is costly, don't. Most ADO.NET providers implement connection pooling. When .Dispose() or .Close() is called on a connection, it's reset and put in a connection pool, ready for reuse.

– Panagiotis Kanavos
Nov 13 '18 at 15:19

DBConnection is a bug. You shouldn't have a global connection. A connection should be opened right before it's used and closed as soon as possible. Locks taken while executing queries remain until a connection is closed. This means they end up blocking other connections.

– Panagiotis Kanavos
Nov 13 '18 at 15:16

Everytime you are opening the connection, where is your connection closing also you have used var conn which will neglect the static conn

– Hassaan
Nov 13 '18 at 15:18

If you want a generic, reusable DbConnection abstraction just use the classes already provided by ADO.NET. All ADO.NET provider classes inherit from abstract classes like DbConnection, DbCommand, DbDataReader

– Panagiotis Kanavos
Nov 13 '18 at 15:18

If you worry that opening and closing a connection is costly, don't. Most ADO.NET providers implement connection pooling. When .Dispose() or .Close() is called on a connection, it's reset and put in a connection pool, ready for reuse.

– Panagiotis Kanavos
Nov 13 '18 at 15:19

add a comment |

2 Answers
2

active

oldest

votes

your method defines a local var conn instead of asigning to the one you define on class level. Omit var:

 conn = new NpgsqlConnection(connstring);

answered Nov 13 '18 at 15:15

apomene

10.8k83456

Nice catch ... did you just washed your eyes .. :)

– Rahul
Nov 13 '18 at 15:16

add a comment |

-1

Remove keyword 'var' from the following statement:

var conn = new NpgsqlConnection(connstring);

answered Nov 13 '18 at 15:20

Naresh

Thanks! Dont know why I put it there. Ofcourse it should be gone! Thanks a lot!

– Daniel Strömberg
Nov 13 '18 at 15:22

Please vote me if my answer makes sense!

– Naresh
Nov 13 '18 at 15:25

add a comment |

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2 Answers
2

active

oldest

votes

2 Answers
2

active

oldest

votes

your method defines a local var conn instead of asigning to the one you define on class level. Omit var:

 conn = new NpgsqlConnection(connstring);

answered Nov 13 '18 at 15:15

apomene

10.8k83456

Nice catch ... did you just washed your eyes .. :)

– Rahul
Nov 13 '18 at 15:16

add a comment |

your method defines a local var conn instead of asigning to the one you define on class level. Omit var:

 conn = new NpgsqlConnection(connstring);

answered Nov 13 '18 at 15:15

apomene

10.8k83456

Nice catch ... did you just washed your eyes .. :)

– Rahul
Nov 13 '18 at 15:16

add a comment |

your method defines a local var conn instead of asigning to the one you define on class level. Omit var:

 conn = new NpgsqlConnection(connstring);

answered Nov 13 '18 at 15:15

apomene

10.8k83456

your method defines a local var conn instead of asigning to the one you define on class level. Omit var:

 conn = new NpgsqlConnection(connstring);

answered Nov 13 '18 at 15:15

apomene

10.8k83456

answered Nov 13 '18 at 15:15

apomene

10.8k83456

answered Nov 13 '18 at 15:15

apomene

10.8k83456

answered Nov 13 '18 at 15:15

apomene

10.8k83456

Nice catch ... did you just washed your eyes .. :)

– Rahul
Nov 13 '18 at 15:16

add a comment |

Nice catch ... did you just washed your eyes .. :)

– Rahul
Nov 13 '18 at 15:16

Nice catch ... did you just washed your eyes .. :)

– Rahul
Nov 13 '18 at 15:16

add a comment |

-1

Remove keyword 'var' from the following statement:

var conn = new NpgsqlConnection(connstring);

answered Nov 13 '18 at 15:20

Naresh

Thanks! Dont know why I put it there. Ofcourse it should be gone! Thanks a lot!

– Daniel Strömberg
Nov 13 '18 at 15:22

Please vote me if my answer makes sense!

– Naresh
Nov 13 '18 at 15:25

add a comment |

-1

Remove keyword 'var' from the following statement:

var conn = new NpgsqlConnection(connstring);

answered Nov 13 '18 at 15:20

Naresh

Thanks! Dont know why I put it there. Ofcourse it should be gone! Thanks a lot!

– Daniel Strömberg
Nov 13 '18 at 15:22

Please vote me if my answer makes sense!

– Naresh
Nov 13 '18 at 15:25

add a comment |

-1

Remove keyword 'var' from the following statement:

var conn = new NpgsqlConnection(connstring);

answered Nov 13 '18 at 15:20

Naresh

Remove keyword 'var' from the following statement:

var conn = new NpgsqlConnection(connstring);

answered Nov 13 '18 at 15:20

Naresh

answered Nov 13 '18 at 15:20

Naresh

answered Nov 13 '18 at 15:20

Naresh

answered Nov 13 '18 at 15:20

Naresh

Thanks! Dont know why I put it there. Ofcourse it should be gone! Thanks a lot!

– Daniel Strömberg
Nov 13 '18 at 15:22

Please vote me if my answer makes sense!

– Naresh
Nov 13 '18 at 15:25

add a comment |

Thanks! Dont know why I put it there. Ofcourse it should be gone! Thanks a lot!

– Daniel Strömberg
Nov 13 '18 at 15:22

Please vote me if my answer makes sense!

– Naresh
Nov 13 '18 at 15:25

Thanks! Dont know why I put it there. Ofcourse it should be gone! Thanks a lot!

– Daniel Strömberg
Nov 13 '18 at 15:22

Please vote me if my answer makes sense!

– Naresh
Nov 13 '18 at 15:25

add a comment |

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