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Select Query works but Update Query does not work in Postgresql from dot net code using NpgsqlCommand

I am trying to update username from MVC .Net C# after connecting Postgres SQL.
I am able to establish the connection and if I run select command I am able to get the result.
But when I am trying to update record no error comes but updated count comes 0. Record available in database.
Can you please suggest what could be the reason.
using (NpgsqlConnection con = new NpgsqlConnection(connectionString))
{
string query = string.Format("UPDATE um_user SET um_user_name='{0}' WHERE um_user_name='{1}'", updatedUser, userNameToBeUpdated);
con.Open();
NpgsqlCommand comn = new NpgsqlCommand(query, con);
comn.Connection = con;
updatedRows = comn.ExecuteNonQuery();
comn.Dispose();
con.Close();
}
I have added using parameter as well with the following code but still getting 0 updtaed rows.
using (NpgsqlConnection connection = new NpgsqlConnection())
{
connection.ConnectionString = connectionString;
connection.Open();
NpgsqlCommand cmd = new NpgsqlCommand();
cmd.Connection = connection;
cmd.CommandText = "update um_user set um_user_name=#newName where um_user_name=#oldName";
cmd.CommandType = CommandType.Text;
cmd.Parameters.Add(new NpgsqlParameter("#newName", updatedUser));
cmd.Parameters.Add(new NpgsqlParameter("#oldName", userNameToBeUpdated));
updatedRows = cmd.ExecuteNonQuery();
cmd.Dispose();
connection.Close();
}

Data not appearing in SQL Database

I'm trying to INSERT data into my SQL database but its not showing anything at all.
This is a for an online role-playing game . There is no error but when I refresh my browser for phpmyadmin using XAMP, no data is being shown.
MySqlConnection connection = new MySqlConnection(connectionString);
connection.Open();
string checkDatabase = "select * from players where username = #playerName";
MySqlCommand command = new MySqlCommand(checkDatabase, connection);
command.Parameters.AddWithValue("#playerName", player.SocialClubName);
MySqlDataReader reader = command.ExecuteReader();
if(reader.Read())
{
player.SendChatMessage("There is an account with the assiociated Social Club Profile!");
}
else
{
MySqlConnection connection1 = new MySqlConnection(connectionString);
connection1.Open();
string playerInsert = "insert into players(username,password) VALUES (#user,#password)";
MySqlCommand command1 = new MySqlCommand(playerInsert, connection1);
command1.Parameters.AddWithValue("#user", player.SocialClubName);
command1.Parameters.AddWithValue("#password", password);
connection1.Close();
}
connection.Close();

You need to execute the query. Try:
...
command1.ExecuteNonQuery();

That's cause you are not executing the query at all as can be seen in below posted code
string playerInsert = "insert into players(username,password) VALUES (#user,#password)";
MySqlCommand command1 = new MySqlCommand(playerInsert, connection1);
command1.Parameters.AddWithValue("#user", player.SocialClubName);
command1.Parameters.AddWithValue("#password", password);
command1.ExecuteNonQuery(); //execute the query
connection1.Close();

Asp.Net SQL Update Statement

I have an Asp.net application on my page the user requests for a user to be removed. This then populates my 'Admin_TaskList' db.
An administrator then goes in the secure area of the site and enters the users name and clicks a button. Upon the confirmation, the user is then deleted from my 'Users' db (already got this working) but I want my 'Admin_TaskList' db 'Status' column to change from 'To Do' to 'Completed'.
As I sad I have the delete bit working but I am struggling updating my other table.
Snippet of code I have tried
conn.Open();
SqlCommand cmd2 = new SqlCommand("UPDATE FROM Admin_TaskList SET Status = 'Complete' WHERE Description = 'Remove User' AND Name = #Name", conn);
cmd2.Parameters.AddWithValue("#Name", txtRemoveUser.Text);
SqlDataReader rd2 = cmd2.ExecuteReader();
conn.Close();
Full code
public void btnRemoveConfirmYes_Click(object sender, EventArgs e)
{
string connection = ConfigurationManager.ConnectionStrings["PaydayLunchConnectionString1"].ConnectionString;
SqlConnection conn = new SqlConnection(connection);
conn.Open();
SqlCommand cmd1 = new SqlCommand("DELETE FROM Users WHERE Name = #Name", conn);
cmd1.Parameters.AddWithValue("#Name", txtRemoveUser.Text);
SqlDataReader rd1 = cmd1.ExecuteReader();
conn.Close();
conn.Open();
SqlCommand cmd2 = new SqlCommand("UPDATE FROM Admin_TaskList SET Status = 'Complete' WHERE Description = 'Remove User' AND Name = #Name", conn);
cmd2.Parameters.AddWithValue("#Name", txtRemoveUser.Text);
SqlDataReader rd2 = cmd2.ExecuteReader();
conn.Close();
txtRemoveUser.Text = "";
Response.Redirect("/AdminSide/TaskList.aspx");
}

Instead of using a SqlDataReader to update a value use SqlCommand.ExecuteNonQuery:
int updated = cmd2.ExecuteNonQuery();
Remember that you need to use ExecuteNonQuery on commands that modify your data like Delete, Insert or Update.
MSDN:
You can use the ExecuteNonQuery to perform catalog operations (for
example, querying the structure of a database or creating database
objects such as tables), or to change the data in a database without
using a DataSet by executing UPDATE, INSERT, or DELETE statements.
The complete method:
int deleted, updated;
string connection = ConfigurationManager.ConnectionStrings["PaydayLunchConnectionString1"].ConnectionString;
using (var conn = new SqlConnection(connection))
{
conn.Open();
string delSql = "DELETE FROM Users WHERE Name = #Name";
using (var cmd = new SqlCommand(delSql, conn))
{
cmd.Parameters.Add("#Name", SqlDbType.NVarChar).Value = txtRemoveUser.Text;
deleted = cmd.ExecuteNonQuery();
}
string updSql = #"UPDATE Admin_TaskList
SET Status = 'Complete'
WHERE Description = 'Remove User'
AND Name = #Name";
using (var cmd = new SqlCommand(updSql, conn))
{
cmd.Parameters.Add("#Name", SqlDbType.NVarChar).Value = txtRemoveUser.Text;
updated = cmd.ExecuteNonQuery();
}
}

How to insert data into a database table using a SqlCommand

I am trying to insert data into a database that I have that has a table called EmployeeInfo
The user is prompted to enter a last name and select a department ID (displayed to the user as either marketing or development) The column ID automatically increments.
Here is my Code behind
protected void SubmitEmployee_Click(object sender, EventArgs e)
{
var submittedEmployeeName = TextBox1.Text;
var submittedDepartment = selectEmployeeDepartment.Text;
if (submittedEmployeeName == "")
{
nameError.Text = "*Last name cannot be blank";
}
else
{
System.Data.SqlClient.SqlConnection sqlConnection1 =
new System.Data.SqlClient.SqlConnection("ConnString");
System.Data.SqlClient.SqlCommand cmd = new System.Data.SqlClient.SqlCommand();
cmd.CommandType = System.Data.CommandType.Text;
cmd.CommandText = "INSERT INTO EmployeeInfo (LastName, DepartmentID ) VALUES ('" + submittedEmployeeName + "', " + submittedDepartment + ")";
cmd.Connection = sqlConnection1;
sqlConnection1.Open();
cmd.ExecuteNonQuery();
sqlConnection1.Close();
}
}
The error I'm recieving is 'Arguement exception was unhandled by user code'
Here is a picture of it.
As requested. More details

If I had enough reputation, I would rather post this as a reply, but it might actually be the solution.
The reason why it stops there is because you are not providing a legit SqlConnection, since your input is: "ConnString", which is just that text.
The connection string should look something like:
const string MyConnectionString = "SERVER=localhost;DATABASE=DbName;UID=userID;PWD=userPW;"
Which in your case should end up like:
System.Data.SqlClient.SqlConnection sqlConnection1 = new System.Data.SqlClient.SqlConnection(MyConnectionString);
Besides that, you should build your connections like following:
using (SqlConnection con = new SqlConnection(MyConnectionString)) {
using (SqlCommand cmd = new SqlCommand())
{
cmd.CommandText = xxxxxx; // Your query to the database
cmd.Connection = con;
cmd.Connection.Open();
cmd.ExecuteNonQuery();
}
}
This will do the closing for you and it also makes it easier for you to nestle connections. I did a project recently and did the connection your way, which ended up not working when I wanted to do more than one execute in one function. Just important to make a new command for each execute.

inserting and deleting not happening in local database (.sdf)

When I try to select values from a local database it executes without any issue. But when I try to insert and delete it's executing the query but it's not affecting any rows.
This is the code I'm using to delete row from my local database:
SqlCeConnection sqlConnection1 = new SqlCeConnection();
sqlConnection1.ConnectionString = "Data Source = Database1.sdf";
SqlCeCommand cmd = sqlConnection1.CreateCommand();
cmd.CommandType = System.Data.CommandType.Text;
cmd.CommandText = "DELETE FROM table1 WHERE slno=2";
cmd.Connection = sqlConnection1;
sqlConnection1.Open();
cmd.Prepare();
int aff=cmd.ExecuteNonQuery();//here its returning '0'
MessageBox.Show(aff.ToString());
sqlConnection1.Dispose();
sqlConnection1.Close();

It is possible that the delete won't affect any rows.
As an aside, I would advise using the using statement in your code:
using (SqlCeConnection conn = new SqlCeConnection("Data Source = Database1.sdf"))
using (SqlCeCommand comm = new SqlCeCommand("DELETE FROM table1 WHERE slno = 2", conn))
{
conn.Open();
comm.CommandType = CommandType.Text;
comm.ExecuteNonQuery();
}
This will handle disposal of relevant objects for you.
Assuming that the SQL is relevant to your database and that you have successfully connected using the connection string beforehand, then the above could will perform a delete action against your database.