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issue with fetching value from 2md datagridview in c#

i have a problem in fetching value from data gridview. In the same event i am able to fetch value from datagrid view1 but in same event i am not able to fetch the value from datagridview2. Help me with correction in following code.
private void button2_Click(object sender, EventArgs e)
{
SqlConnection con = new SqlConnection(path);
SqlConnection con1 = new SqlConnection(path);
con.Open();
string selectSql = "select * from textbooks where class='" + txt_class.Text.ToString() + "'";
SqlCommand cmd = new SqlCommand(selectSql, con);
string textname = "";
tempcnt.Text = "test";
string bookname = "";
double bookquantity = 0;
string textname1 = "";
string bookname1 = "";
double stockquantity1 = 0;
double bookquantity1 = 0;
using (SqlDataReader reader = cmd.ExecuteReader())
{
while (reader.Read())
{
bookname = (reader["name"].ToString());
bookquantity = Convert.ToInt32(reader["quantity"]);
for (int i = 0; i < dataGridView1.Rows.Count; ++i)
{
textname = Convert.ToString(dataGridView1.Rows[i].Cells[0].Value);
if (textname == bookname)
{
bookquantity = bookquantity - 1;
temp_count.Text = bookquantity.ToString();
con1.Open();
string uquery = "update textbooks set quantity=" + bookquantity + " where name='" + bookname + "'";
SqlCommand cmd1 = new SqlCommand(uquery, con1);
cmd1.ExecuteNonQuery();
con1.Close();
}
}
}
}
con.Close();
con.Open();
string selectSql2 = "select * from notebooks";
SqlCommand cmd2 = new SqlCommand(selectSql2, con);
tempcnt.Text = "test";
using (SqlDataReader reader1 = cmd2.ExecuteReader())
{
while (reader1.Read())
{
bookname1 = (reader1["name"].ToString());
stockquantity1 = Convert.ToInt32(reader1["quantity"]);
tempcnt.Text = bookname1;
for (int i = 0; i < dataGridView2.Rows.Count; i++)
{
textname1 = dataGridView2.Rows[i].Cells[0].Value as string;
string temp = Convert.ToString(dataGridView2.Rows[i].Cells[0].Value);
tempcnt.Text = temp;
if (temp == bookname1)
{
tempcnt.Text = "success";
}
}
}
}
con.Close();
}

I cant insert data into my DB

I'm trying to insert data into my DB and when i press the button it should get done but it won't
I guess it's from my last layer somewhere in my Query
here's my code
public void InsertInventory(DateTime _date, int _customer_Id,
int _employee_Id, List<int> _product_Id,
List<int> _amountSold,
List<int> _unitPrice, List<int> _totalPrice)
{
Connection_String = #"Data Source=MOSTAFA-PC;Initial Catalog="
+ "Sales and Inventory System"
+ ";Integrated Security=TrueData Source=MOSTAFA-PC;Initial Catalog="
+ "Sales and Inventory System"
+ ";Integrated Security=True;";
Query = "insert into Inventory" +
"(Customer_Id,Employee_Id,Product_Id,[Date],[Amount Sold],[Unit Price],[Total Price])" +
"values (#customer_id,#Employee_id,#Product_id,#[Date],#[Amount_Sold],#[Unit_Price],#[Total_Price])";
using (Con = new SqlConnection(Connection_String))
using (Cmd = new SqlCommand(Query, Con))
{
Cmd.Parameters.Add("#customer_id", SqlDbType.Int);
Cmd.Parameters.Add("#Employee_id", SqlDbType.Int);
Cmd.Parameters.Add("#Product_id", SqlDbType.Int);
Cmd.Parameters.Add("#[Date]", SqlDbType.NVarChar);
//Cmd.Parameters.Add("#[Date]", SqlDbType.Date);
Cmd.Parameters.Add("#[Amount_sold]", SqlDbType.Int);
Cmd.Parameters.Add("#[Unit_Price]", SqlDbType.Decimal);
Cmd.Parameters.Add("#Total_Price", SqlDbType.Decimal);
Cmd.Connection = Con;
Con.Open();
int RecordToAdd = _product_Id.Count;
for (int i = 0; i < RecordToAdd; i++)
{
Cmd.Parameters["#customer_id"].Value = _customer_Id;
Cmd.Parameters["#Employee_id"].Value = _employee_Id;
Cmd.Parameters["#Product_id"].Value = _product_Id;
Cmd.Parameters["#Date"].Value = _date;
Cmd.Parameters["#Amount_sold"].Value = _amountSold;
Cmd.Parameters["#Unit_Price"].Value = _unitPrice;
Cmd.Parameters["#Total_Price"].Value = _totalPrice;
Cmd.ExecuteNonQuery();
}
}
}
I can't figure it out where my problem is

The problem is caused by the values that you set for your parameters.
You should use the indexer to retrieve an element from the lists not the whole lists
// These doesn't change inside the loop, so set it once for all...
Cmd.Parameters["#customer_id"].Value = _customer_Id;
Cmd.Parameters["#Employee_id"].Value = _employee_Id;
Cmd.Parameters["#Date"].Value = _date;
for (int i = 0; i < RecordToAdd; i++)
{
Cmd.Parameters["#Product_id"].Value = _product_Id[i];
Cmd.Parameters["#Amount_sold"].Value = _amountSold[i];
Cmd.Parameters["#Unit_Price"].Value = _unitPrice[i];
Cmd.Parameters["#Total_Price"].Value = _totalPrice[i];
Cmd.ExecuteNonQuery();
}

Using for loop to delete data in database

I want to delete every item in the array from the database.
string[] ids = dt.AsEnumerable()
.Select(row => row["ProductID"].ToString())
.ToArray();
for (int i = 0; i <= ids.Length; i++) {
string val = ids[i];
MySqlCommand cmd1 = new MySqlCommand();
cmd1.CommandText = "Delete from tblindividualproduct where ProductID = #p1";
cmd1.Parameters.AddWithValue("#p1", val);
}
When I run this the line
string val = ids[i];
gives me an error which says:
Index was outside the bounds of the array.
What's wrong with this?
This is my whole code UPDATED
string connString = "Server=192.168.1.100;Database=product;Uid=newuser;Pwd=password";
MySqlConnection conn = new MySqlConnection(connString);
string[] ids = dt.AsEnumerable()
.Select(row => row["ProductID"].ToString())
.ToArray();
try
{
MySqlCommand cmd1 = new MySqlCommand();
conn.Open();
cmd1.CommandText = "Delete from tblindividualproduct where ProductID = #p1";
cmd1.Parameters.AddWithValue("#p1", "");
for (int i = 0; i < ids.Length; i++)
{
string val = ids[i];
cmd1.Parameters[0].Value = val;
cmd1.ExecuteNonQuery();
}
MessageBox.Show("Checkout Successful");
}

Arrays in .NET are zero based and thus the valid indexes go from zero to length - 1.
You should change your code to
for (int i = 0; i < ids.Length; i++)
As pointed by other answer you loop also fails to call cmd1.ExecuteNonQuery and it seems that you don't have associated a connection to the MySqlCommand (thus it will not work at all).
An interesting variation on your code could be to create a single string with all of your commands and submit the command just one time.
Beware that this is not recommended unless you are absolutely sure that your ID are just numbers and not coming from user input
StringBuilder sb = new StringBuilder();
for (int i = 0; i <= ids.Length; i++)
sb.AppendFormat("Delete from tblindividualproduct where ProductID = {0};", ids[i]);
MySqlCommand cmd1 = new MySqlCommand();
cmd1.CommandText = sb.ToString();
cmd1.Connection = connection;
cmd1.ExecuteNonQuery();

Array indexes go from 0 up to Length - 1, so you need to stop the loop before i == ids.Length. Try replacing the <= with <. Also, don't forget to call ExecuteNonQuery to execute your command.
for (int i = 0; i < ids.Length; i++) {
string val = ids[i];
MySqlCommand cmd1 = new MySqlCommand(conn);
cmd1.CommandText = "Delete from tblindividualproduct where ProductID = #p1";
cmd1.Connection = conn;
cmd1.Parameters.AddWithValue("#p1", val);
cmd1.ExecuteNonQuery();
}
You can also set up the command outside of the loop and only set the parameter and execute the command inside the loop:
MySqlCommand cmd1 = new MySqlCommand(conn);
cmd1.CommandText = "Delete from tblindividualproduct where ProductID = #p1";
cmd1.Connection = conn;
cmd1.Parameters.AddWithValue("#p1", "");
for (int i = 0; i < ids.Length; i++) {
string val = ids[i];
cmd1.Parameters[0].Value = val;
cmd1.ExecuteNonQuery();
}

This will be much more efficient as there's only one call to the DB, plus there's no need anymore to iterate through yours ids collection.
string[] ids = dt.AsEnumerable()
.Select(row => row["ProductID"].ToString())
.ToArray();
MySqlCommand cmd1 = new MySqlCommand();
cmd1.CommandText = "Delete from tblindividualproduct where ProductID IN (" + String.Join(",", ids) + ")";

Your index goes from 0 to your length -1 like this:
tring[] ids = dt.AsEnumerable()
.Select(row => row["ProductID"].ToString())
.ToArray();
for (int i = 0; i < ids.Length; i++) {
string val = ids[i];
MySqlCommand cmd1 = new MySqlCommand();
cmd1.CommandText = "Delete from tblindividualproduct where ProductID = #p1";
cmd1.Parameters.AddWithValue("#p1", val);
}
And Index was outside the bounds of the array. means that your accessed an element that does not exist with that index.

How do multi rows insert with MySqlCommand and prepare statement?(#C)

Mysql give example how insert rows with prepare statement and .NET:
http://dev.mysql.com/doc/refman/5.5/en/connector-net-programming-prepared.html
Its looks that its works like that,because in the end of each iteration call to:cmd.ExecuteNonQuery():
INSERT INTO VALUES()...;INSERT INTO VALUES()...;INSERT INTO VALUES()...;
Can it done with use of prepare statement like that:
INSERT INTO all values...
More explanations::
The code in mysql example (cmd.ExecuteNonQuery() in each iteration):
MySql.Data.MySqlClient.MySqlConnection conn;
MySql.Data.MySqlClient.MySqlCommand cmd;
conn = new MySql.Data.MySqlClient.MySqlConnection();
cmd = new MySql.Data.MySqlClient.MySqlCommand();
conn.ConnectionString = strConnection;
try
{
conn.Open();
cmd.Connection = conn;
cmd.CommandText = "INSERT INTO myTable VALUES(NULL, #number, #text)";
cmd.Prepare();
cmd.Parameters.AddWithValue("#number", 1);
cmd.Parameters.AddWithValue("#text", "One");
for (int i=1; i <= 1000; i++)
{
cmd.Parameters["#number"].Value = i;
cmd.Parameters["#text"].Value = "A string value";
cmd.ExecuteNonQuery();
}
}
*The code that i want to have like that(cmd.ExecuteNonQuery(); after all iterations): *
MySql.Data.MySqlClient.MySqlConnection conn;
MySql.Data.MySqlClient.MySqlCommand cmd;
conn = new MySql.Data.MySqlClient.MySqlConnection();
cmd = new MySql.Data.MySqlClient.MySqlCommand();
conn.ConnectionString = strConnection;
try
{
conn.Open();
cmd.Connection = conn;
cmd.CommandText = "INSERT INTO myTable VALUES(NULL, #number, #text)";
cmd.Prepare();
cmd.Parameters.AddWithValue("#number", 1);
cmd.Parameters.AddWithValue("#text", "One");
for (int i=1; i <= 1000; i++)
{
cmd.Parameters["#number"].Value = i;
cmd.Parameters["#text"].Value = "A string value";
}
cmd.ExecuteNonQuery();
}

Try this:
using (var connection = new MySqlConnection("your connection string"))
{
connection.Open();
// first we'll build our query string. Something like this :
// INSERT INTO myTable VALUES (NULL, #number0, #text0), (NULL, #number1, #text1)...;
StringBuilder queryBuilder = new StringBuilder("INSERT INTO myTable VALUES ");
for (int i = 0; i < 10; i++)
{
queryBuilder.AppendFormat("(NULL,#number{0},#text{0}),", i);
//once we're done looping we remove the last ',' and replace it with a ';'
if (i == 9)
{
queryBuilder.Replace(',', ';', queryBuilder.Length - 1, 1);
}
}
MySqlCommand command = new MySqlCommand(queryBuilder.ToString(), connection);
//assign each parameter its value
for (int i = 0; i < 10; i++)
{
command.Parameters.AddWithValue("#number" + i, i);
command.Parameters.AddWithValue("#text" + i, "textValue");
}
command.ExecuteNonQuery();
}

Convert InnerHtml values into Decimal

Im trying to convert InnerHtml values to Decimal value. The user will input an XPath into textBox2
List<Decimal> productPriceList = new List<Decimal>();
var priceTags = document.DocumentNode.SelectNodes(textBox2.Text);
Then I do a foreach loop to iterate though the prices found and add them to a list called productPriceList
foreach (var prices in priceTags)
{
label9.Visible = true;
label9.Text += prices.InnerHtml + "\n";
productPriceList.Add(prices.InnerHtml);
label2.Visible = false;
label3.Visible = false;
}
Then I add the values into the database:
using (var con = new SqlConnection(connectionString))
{
con.Open();
using (var cmd = new SqlCommand(#"INSERT INTO OnlineProductsTemp$(CompetitorID, ProductCode, ProductName, DateCaptured)
VALUES(#CompetitorID, #ProductCode, #ProductName, #DateCaptured)", con))
{
cmd.Parameters.Add("#CompetitorID", SqlDbType.Int);
cmd.Parameters.Add("#ProductCode", SqlDbType.VarChar);
cmd.Parameters.Add("#ProductName", SqlDbType.VarChar);
cmd.Parameters.Add("#Price", SqlDbType.Decimal);
cmd.Parameters.Add("#DateCaptured", SqlDbType.DateTime);
for (int i = 0; i < competitorList.Count; i++)
{
cmd.Parameters["#CompetitorID"].Value = competitorList[i];
cmd.Parameters["#ProductCode"].Value = productCodeList[i];
cmd.Parameters["#ProductName"].Value = productNameList[i];
cmd.Parameters["#Price"].Value = productPriceList[i];
cmd.Parameters["#DateCaptured"].Value = dateCapturedList[i];
int rowsAffected = cmd.ExecuteNonQuery();
}
Everything works correctly but I cant seem to find a way to correctly convert InnerHtml values to a Decimal type. Is there a way of achieving this?

Depending on your values that come from inner html you can do something like this
using (var con = new SqlConnection(connectionString))
{
con.Open();
using (var cmd = new SqlCommand(#"INSERT INTO OnlineProductsTemp$(CompetitorID, ProductCode, ProductName, DateCaptured)
VALUES(#CompetitorID, #ProductCode, #ProductName, #DateCaptured)", con))
{
cmd.Parameters.Add("#CompetitorID", SqlDbType.Int);
cmd.Parameters.Add("#ProductCode", SqlDbType.VarChar);
cmd.Parameters.Add("#ProductName", SqlDbType.VarChar);
cmd.Parameters.Add("#Price", SqlDbType.Decimal);
cmd.Parameters.Add("#DateCaptured", SqlDbType.DateTime);
for (int i = 0; i < competitorList.Count; i++)
{
cmd.Parameters["#CompetitorID"].Value = competitorList[i];
cmd.Parameters["#ProductCode"].Value = productCodeList[i];
cmd.Parameters["#ProductName"].Value = productNameList[i];
cmd.Parameters["#Price"].Value = productPriceList[i];
cmd.Parameters["#DateCaptured"].Value = dateCapturedList[i];
int rowsAffected = cmd.ExecuteNonQuery(); // also the variable rowsAffected is not visible outside the scope of the for loop
}
}
}
Update:
You should, then, convert the values prior to adding them in the list, like so:
foreach (var prices in priceTags)
{
label9.Visible = true;
label9.Text += prices.InnerHtml + "\n";
productPriceList.Add(Decimal.Parse(prices.InnerHtml, <cultureInfoHere>));
label2.Visible = false;
label3.Visible = false;
}
By doing this you don't have to change the list type.