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Textbox Auto Number generated in c# error

I am creating a simple product form in c#. while I generated auto number getting error what I tried so far i attached below.product id starts with 00001. I created a method Getproduct() inside the method I wrote the code.error displayed syntax error.
public void Getproduct() {
string sql;
SqlConnection con = new SqlConnection("server =.; initial catalog=product; integrated security=true");
SqlDataAdapter dr;
SqlDataReader dr1;
sql = "SELECT id,product_name,product_desc,price FROM product Order By id Desc";
SqlCommand com = new SqlCommand(sql, con);
SqlDataReader dr = com.ExecuteReader();
if (dr.Read() == true) {
int id;
int pid;
id = (dr[0] + 1);
pid = id.ToString("00000");
else if IsDBNull(dr) {
pid = ("00001");
}
}
}

Try this code
public void Getproduct()
{
string sql;
SqlConnection con = new SqlConnection("server =.; initial catalog=product; integrated security=true");
SqlDataAdapter dapt;
SqlDataReader dr1;
sql = "SELECT id,product_name,product_desc,price FROM product Order By id Desc";
SqlCommand com = new SqlCommand(sql, con);
SqlDataReader dr = com.ExecuteReader();
int id;
string pid;
if (dr.Read() == true)
{
int val = 0;
Int32.TryParse(dr[0].ToString(),out val);
id = ( val + 1);
pid = id.ToString("00000");
}
else if( Convert.IsDBNull(dr) )
{
pid = ("00001");
}
}

Assign SQL query result to session variable

I am trying to run a SQL query based on who's logged in which gets the Team_ID and assigns it to the session variable. I am having trouble assigning the result to the variable.
protected void ButtonLogin_Click(object sender, EventArgs e)
{
//check what user category was selected and login to appropriate page
if (DropDownListUserType.SelectedIndex == 1)
{
SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["Web_FussConnectionString"].ConnectionString);
con.Open();
SqlCommand cmd = new SqlCommand("select * from Team_User where Email = #username and Password_1 = #password", con);
cmd.Parameters.AddWithValue("#username", UserName.Text);
cmd.Parameters.AddWithValue("#password", Password.Text);
SqlCommand cmdID = new SqlCommand("select Team_ID from Team_User where Email = #username and Password_1 = #password", con);
cmdID.Parameters.AddWithValue("#username", UserName.Text);
cmdID.Parameters.AddWithValue("#password", Password.Text);
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataTable dt = new DataTable();
da.Fill(dt);
if (dt.Rows.Count > 0)
{
SqlDataReader reader = cmdID.ExecuteReader();
int Team_ID = reader.GetInt32(1);
Session["Team_ID"] = Team_ID;
Response.Redirect("AddPlayer.aspx");
}
else
{
ClientScript.RegisterStartupScript(Page.GetType(), "validation", "<script language='javascript'>alert('Invalid Username and Password')</script>");
}
}
}

Your code doesn't make a whole lot of sense....
If you only want the Team_ID - why are you loading the whole row first, and then call the database again to get just the Team_ID???
I tried to simplify your code a good bit:
protected void ButtonLogin_Click(object sender, EventArgs e)
{
// check what user category was selected and login to appropriate page
if (DropDownListUserType.SelectedIndex == 1)
{
// define connection string and SQL query as strings
string connectionString = ConfigurationManager.ConnectionStrings["Web_FussConnectionString"].ConnectionString;
string query = "SELECT Team_ID FROM dbo.Team_User WHERE Email = #username AND Password_1 = #password";
// set up SqlConnection and SqlCommand in "using" blocks
using (SqlConnection con = new SqlConnection(connectionString))
using (SqlCommand cmd = new SqlCommand(query, con))
{
// define and fill parameters - DO NOT use .AddWithValue!
cmd.Parameters.Add("#username", SqlDbType.VarChar, 100).Value = UserName.Text;
cmd.Parameters.Add("#password", SqlDbType.VarChar, 100).Value = Password.Text;
// open connection, execute scalar, close connection
con.Open();
object result = cmd.ExecuteScalar();
// if we got back a result ....
if(result != null)
{
int teamID = Convert.ToInt32(result.ToString());
Session["Team_ID"] = teamID;
Response.Redirect("AddPlayer.aspx");
}
else
{
// if result is NULL, then the username+password
// were NOT found - do what needs to be done in that case here
}
}
}
}

Populate textbox with selected items from database

private void fillProduct() {
SqlConnection conn = new SqlConnection("Data Source=STATION21\\SQLEXPRESS;Initial Catalog=mydb;Integrated Security=true");
conn.Open();
string query = "Select prodID from product";
SqlCommand cmd = new SqlCommand(query, conn);
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataTable dt = new DataTable();
da.Fill(dt);
if (dt.Rows.Count > 0) {
cmbPCode.DataSource = dt;
cmbPCode.DisplayMember = "prodID";
cmbPCode.ValueMember = "prodID";
}
private void cmbPCode_SelectedIndexChanged(object sender, EventArgs e)
{
SqlConnection con = new SqlConnection("Data Source=STATION21\\SQLEXPRESS;Initial Catalog=mydb;Integrated Security=true");
con.Open();
string query = "Select * from product where prodID = '"+cmbPCode.Text+"'".ToString();
SqlCommand cmd = new SqlCommand(query, con);
SqlDataReader dr = cmd.ExecuteReader();
if (dr.Read()) {
tbdc.Text = dr["prodDescription"].ToString();
}
}
i am having trouble with getting my items from the database according to the selected index i get this error
Conversion failed when converting the varchar value
'System.Data.DataRowView' to data type int
can someone please help me how to convert SqlDataReader to String. because i notice that when i retrieve a column with varchar/string datatype i am not having this kind error but if i retrieve a column with int datatype i get this error.

Replace This:
string query = "Select * from product where prodID = '"+cmbPCode.Text+
"'".ToString();
With This:
string query = "Select * from product where prodID = "+cmbPCode.Text;
Suggestion: Your query is open to SQL Injection i would suggest you to use parameterised queries to avoid them.
Using Parameterised Queries:
string query = "Select * from product where prodID = #ID";
SqlCommand cmd = new SqlCommand(query, con);
cmd.Parameters.AddWithValue("#ID",cmbPCode.Text);

SQL update command not working

I have created a web page in Asp.net website. The following page load will run as it gets arguments from previous page. The page also has an option for editing the contents and updating in database. But when the button(save) is clicked it doesn't update the database.Kindly help in this. But when there is no connection in page load the update command works.
protected void Page_Load(object sender, EventArgs e)
{
String cust=Request.QueryString["custName"];
String env = Request.QueryString["env"];
SqlConnection cnn = new SqlConnection();
string connStr = ConfigurationManager.ConnectionStrings["cnn"].ConnectionString;
SqlDataAdapter adapter = new SqlDataAdapter();
cnn.ConnectionString = connStr;
cnn.Open();
view();
if (env == "Production")
{
DataSet MyDataSet = new DataSet();
adapter = new SqlDataAdapter("Select * from Customer_Production where Customer_Name=#cust", cnn);
SqlCommandBuilder m_cbCommandBuilder = new SqlCommandBuilder(adapter);
cnn.Close();
//SqlCommand cmd = new SqlCommand("Select * from Customer_Production where Customer_Name=#cust", cnn);
adapter.SelectCommand.Parameters.AddWithValue("#cust", cust);
adapter.Fill(MyDataSet, "Servers");
foreach (DataRow myRow in MyDataSet.Tables[0].Rows)
{
custName.Value = myRow["Customer_name"].ToString();
custMaintain.Value= myRow["Customer_Maintenance"].ToString();
serviceAffect.Value=myRow["Systems/Services_Affected"].ToString();
email_Content.Value= myRow["Email_Content"].ToString();
email_Signature.Value= myRow["Email_Signature"].ToString();
email_From.Value=myRow["Email_From"].ToString();
email_To.Value=myRow["Email_To"].ToString();
email_Cc.Value=myRow["Email_Cc"].ToString();
email_Bcc.Value=myRow["Email_Bcc"].ToString();
}
}
else
{
DataSet MyDataSet = new DataSet();
adapter = new SqlDataAdapter("Select * from Customer_Non_Production where Customer_Name=#cust", cnn);
SqlCommandBuilder m_cbCommandBuilder = new SqlCommandBuilder(adapter);
cnn.Close();
//SqlCommand cmd = new SqlCommand("Select * from Customer_Production where Customer_Name=#cust", cnn);
adapter.SelectCommand.Parameters.AddWithValue("#cust", cust);
adapter.Fill(MyDataSet, "Servers");
foreach (DataRow myRow in MyDataSet.Tables[0].Rows)
{
custName.Value = myRow["Customer_name"].ToString();
custMaintain.Value = myRow["Customer_Maintenance"].ToString();
serviceAffect.Value = myRow["Systems/Services_Affected"].ToString();
email_Content.Value = myRow["Email_Content"].ToString();
email_Signature.Value = myRow["Email_Signature"].ToString();
email_From.Value = myRow["Email_From"].ToString();
email_To.Value = myRow["Email_To"].ToString();
email_Cc.Value = myRow["Email_Cc"].ToString();
email_Bcc.Value = myRow["Email_Bcc"].ToString();
}
}
The following is the button click for Save Button(for update command)
protected void save_click(object sender, EventArgs e)
{
//Button Click Save
/* String id = "A";
SqlConnection cnn = new SqlConnection();
string connStr = ConfigurationManager.ConnectionStrings["cnn"].ConnectionString;
SqlDataAdapter adapter = new SqlDataAdapter();
cnn.ConnectionString = connStr;
cnn.Open();
String sql = String.Format("Update Customer_Production set Email_Signature='{0}' where Customer_Name like '{1}'",TextBox1.Text,id);
SqlCommand cmd = new SqlCommand(sql, cnn);
cmd.ExecuteNonQuery();
*/
String cust = "A";
SqlConnection cnn = new SqlConnection();
string connStr = ConfigurationManager.ConnectionStrings["cnn"].ConnectionString;
SqlDataAdapter adapter = new SqlDataAdapter();
cnn.ConnectionString = connStr;
cnn.Open();
if (env.Value == "Production")
{
//String sql = String.Format("Update Customer_Production set Customer_Maintenance='{0}',Environment='{1}',[Systems/Services_Affected]='{2}',Email_Content='{3}',Email_Signature='{4}',Email_To='{5}',Email_Cc='{6}',Email_Bcc='{7}',Email_From='{8}' where Customer_Name like '{9}' ", "custMaintain.Value","env.Value","serviceAffect.Value","email_Content.Value","email_To.Value","email_Cc.Value","email_Bcc.Value","email_From.Value", "cust");
String sql = String.Format("Update Customer_Production set Email_Signature='{0}' where Customer_Name like '{1}'", email_Signature.Value,cust);
SqlCommand cmd = new SqlCommand(sql, cnn);
cmd.ExecuteNonQuery();
}
else
{
}
}

I'm not sure why having a connection (or not) in the Page_Load would make a difference, but here's one thing that looks off to me:
String.Format(
"Update Customer_Production set Email_Signature='{0}' where Customer_Name like '{1}'",
email_Signature.Value,
cust);
(I broke it into several lines because the part I'm interested in is the last part of the format string.)
You've set cust to "A" earlier in that method. So the SQL that will result will look (at the end) like this:
... where Customer_Name like 'A'
Unless you have a customer name that is exactly equal to A, that's not going to return anything, and therefore no records will be updated. You're forgetting the '%' wildcard.
I agree with all those who have pointed out that your code is vulnerable to SQL injection (and you'll also have a problem with single quotes), but just to show you what it needs to look like, here it is with the wildcard:
Update Customer_Production set Email_Signature='{0}' where Customer_Name like '{1}%'

How to get list of all database from sql server in a combobox using c#.net

I am entering the source name userid and password through the textbox and want the database list should be listed on the combo box so that all the four options sourcename, userid, password and databasename can be selected by the user to perform the connectivity
The databases are to be retrieve from other system as per the user. User will enter the IP, userid and password and they should get the database list in the combo box so that they can select the required database and perform the connectivity
private void frmConfig_Load(object sender, EventArgs e)
{
try
{
string Conn = "server=servername;User Id=userid;" + "pwd=******;";
con = new SqlConnection(Conn);
con.Open();
da = new SqlDataAdapter("SELECT * FROM sys.database", con);
cbSrc.Items.Add(da);
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
I am trying to do this but it is not generating any data

sys.databases
SELECT name
FROM sys.databases;
Edit:
I recommend using IDataReader, returning a List and caching the results. You can simply bind your drop down to the results and retrieve the same list from cache when needed.
public List<string> GetDatabaseList()
{
List<string> list = new List<string>();
// Open connection to the database
string conString = "server=xeon;uid=sa;pwd=manager; database=northwind";
using (SqlConnection con = new SqlConnection(conString))
{
con.Open();
// Set up a command with the given query and associate
// this with the current connection.
using (SqlCommand cmd = new SqlCommand("SELECT name from sys.databases", con))
{
using (IDataReader dr = cmd.ExecuteReader())
{
while (dr.Read())
{
list.Add(dr[0].ToString());
}
}
}
}
return list;
}

First add following assemblies:
Microsoft.SqlServer.ConnectionInfo.dll
Microsoft.SqlServer.Management.Sdk.Sfc.dll
Microsoft.SqlServer.Smo.dll
from
C:\Program Files\Microsoft SQL Server\100\SDK\Assemblies\
and then use below code:
var server = new Microsoft.SqlServer.Management.Smo.Server("Server name");
foreach (Database db in server.Databases) {
cboDBs.Items.Add(db.Name);
}

you can use on of the following queries:
EXEC sp_databases
SELECT * FROM sys.databases
Serge

Simply using GetSchema method:
using (SqlConnection connection = GetConnection())
{
connection.Open();
DataTable dtDatabases = connection.GetSchema("databases");
//Get database name using dtDatabases["database_name"]
}

using (var connection = new System.Data.SqlClient.SqlConnection("ConnectionString"))
{
connection.Open();
var command = new System.Data.SqlClient.SqlCommand();
command.Connection = connection;
command.CommandType = CommandType.Text;
command.CommandText = "SELECT name FROM master.sys.databases";
var adapter = new System.Data.SqlClient.SqlDataAdapter(command);
var dataset = new DataSet();
adapter.Fill(dataset);
DataTable dtDatabases = dataset.Tables[0];
}

How to get list of all database from sql server in a combobox using c# asp.net windows application
try
{
string Conn = "server=.;User Id=sa;" + "pwd=passs;";
SqlConnection con = new SqlConnection(Conn);
con.Open();
SqlCommand cmd = new SqlCommand();
// da = new SqlDataAdapter("SELECT * FROM sys.database", con);
cmd = new SqlCommand("SELECT name FROM sys.databases", con);
// comboBox1.Items.Add(cmd);
SqlDataReader dr;
dr = cmd.ExecuteReader();
if (dr.HasRows)
{
while (dr.Read())
{
//comboBox2.Items.Add(dr[0]);
comboBox1.Items.Add(dr[0]);
}
}
// .Items.Add(da);
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}

Try this:
SqlConnection con = new SqlConnection(YourConnectionString);
SqlCommand cmd = new SqlCommand("SELECT name from sys.databases", con);
con.Open();
SqlDataReader dr = cmd.ExecuteReader();
while (dr.Read())
{
cbSrc.Items.Add(dr[0].ToString());
}
con.Close();
or this:
DataSet ds = new DataSet();
SqlDataAdapter sqlda = new SqlDataAdapter("SELECT name from sys.databases", YourConnectionString);
sqlda.Fill(ds);
for (int i = 0; i < ds.Tables[0].Rows.Count; i++)
{
cbSrc.Items.Add(ds.Tables[0].Rows[i][0].ToString());
}

public static List<string> GetAllDatabaseNamesByServerName(string ServerName, [Optional] string UserID, [Optional] string Password)
{
List<string> lstDatabaseNames = null;
try
{
lstDatabaseNames = new List<string>();
//string servername = System.Environment.MachineName;
string newConnString = string.Format("Data Source={0};", ServerName);
if (UserID == null)
{
newConnString += "Integrated Security = True;";
}
else
{
newConnString += string.Format("User Id ={0}; Password={1};", UserID, Password);
}
SqlConnection con = new SqlConnection(newConnString);
con.Open();
SqlCommand cmd = new SqlCommand("SELECT name FROM master.sys.databases", con);
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataTable dt = new DataTable();
da.Fill(dt);
foreach (DataRow row in dt.Rows)
{
lstDatabaseNames.Add(row[0].ToString());
}
con.Close();
return lstDatabaseNames;
}
finally
{
}
}