how to solve error of “ ExecuteNonQuery: Connection property has not been initialized?”

Question

con = new SqlConnection (cs);
SqlCommand UpdateCommand = new SqlCommand("Update Stock Set ConfigID = @ConfigID , Quantity = @Quantity ,TotalPrice =@TotalPrice, StockDate =@StockDate ,Where StockID='" +txtStockID.Text+"'");
UpdateCommand.Parameters.Add("@ConfigID",SqlDbType.Int).Value= txtConfigID.Text;
UpdateCommand.Parameters.Add("@Quantity", SqlDbType.Int).Value = txtQty.Text;
UpdateCommand.Parameters.Add("@TotalPrice", SqlDbType.Int).Value = txtTotalPrice.Text;
UpdateCommand.Parameters.Add("@StockDate", SqlDbType.NVarChar, 50).Value = dtpStockDate.Value;
con.Open();
UpdateCommand.ExecuteNonQuery();

con.Close();

Answer 1

I find this error-message understandable, isn't it? However, you have to assign the connection to the SqlCommand , either by using the constructor or the property Connection :

string updateSQL = @"UPDATE Stock Set ConfigID = @ConfigID, 
                                      Quantity = @Quantity,
                                      TotalPrice = @TotalPrice, 
                                      StockDate = @StockDate 
                     WHERE StockID = @StockID";
SqlCommand UpdateCommand = new SqlCommand(updateSQL, con);

or

SqlCommand UpdateCommand = new SqlCommand(updateSQL);
UpdateCommand.Connection = con;

• Note that i've added a parameter for the StockID in the Where and removed the last comma before the Where .

• Note also that you should close connections when you're finished, therefore you can use the using -statement which ensures that it gets disposed/closed even on error:

   using(var con = new SqlConnection (cs)) { // ... } 

Answer 2

how to solve error of “ ExecuteNonQuery: Connection property has not been initialized?”

By initializing the Connection property

UpdateCommand.Connection = con;  
UpdateCommand.ExecuteNonQuery();

Also you should wrap your connection object with a using statement to make sure it is properly disposed.

Answer 3

You can also use the connection to create the command:

var command = connection.CreateCommand();

This ensures you have a command initialised with the correct connection. You can set the query string using the property command.CommandText :

command.CommandText = @"SELECT foo FROM foo";