I have this code that is suppose to get me the last registered MemberId from column but I cant get it to work, what have I got wrong?
if (con.State == ConnectionState.Open)
{
con.Close();
}
con.Open();
SqlCommand cmd = con.CreateCommand();
cmd.CommandType = CommandType.Text;
cmd.CommandText = "SELECT top 1 * FROM Medleminfo ORDER BY MemberId desc";
cmd.ExecuteNonQuery();
DataTable dt = new DataTable();
SqlDataAdapter da = new SqlDataAdapter(cmd);
da.Fill(dt);
foreach (DataRow dr in dt.Rows)
{
last_id = Convert.ToInt32(dr["MemberId"].ToString());
}
return last_id;
Output last_id is supposed to be used in this method:
public DataTable display_tiger_info(int member_id)
{
if (con.State == ConnectionState.Open)
{
con.Close();
}
con.Open();
SqlCommand cmd = con.CreateCommand();
cmd.CommandType = CommandType.Text;
cmd.CommandText = #"SELECT Medleminfo.MemberId, Medleminfo.Förnamn, Medleminfo.Efternamn,
Medleminfo.Adress, Medleminfo.Telefon, Tigerinfo.Tigernamn,Tigerinfo.Födelsedatum
FROM Medleminfo, Tigerinfo WHERE Medleminfo.MemberId = Tigerinfo.OwnerID ";
cmd.ExecuteNonQuery();
DataTable dt = new DataTable();
SqlDataAdapter da = new SqlDataAdapter(cmd);
da.Fill(dt);
return dt;
}
Why not just use the 'Max' function? This is assuming that your looking for the largest number in the sequence. The way your question is worded though would suggest that you should have a date column to search by instead. Also if you want just one result then try execute scalar instead of putting it into a data table and going through all that extra work.
int id = 0;
using (SqlConnection connection = new SqlConnection(connectionString))
{
connection.Open();
using(var command = new SqlCommand("Select Max(MemberId) from Medleminfo", connection))
{
id = (int)command.ExecuteScalar();
}
}
I think your issues is probably cmd.ExecuteNonQuery() according to the msdn SqlCommand.ExecuteNonQuery Method Executes a Transact-SQL statement against the connection and returns the number of rows affected.
You will probably be wanting to use ExecuteReader in something like the following
if (con.State == ConnectionState.Open)
{
con.Close();
}
con.Open();
SqlCommand cmd = con.CreateCommand();
cmd.CommandType = CommandType.Text;
//All you want is the member Id why get all the columns
cmd.CommandText = "SELECT top 1 MemberId FROM Medleminfo ORDER BY MemberId desc";
SqlDataReader reader = cmd.ExecuteReader();
while (reader.Read())
{
last_id = Convert.ToInt32( reader[0]));
}
return last_id;
UPDATE: This code might solve your problem but I did not identify the issue correctly cmd.ExecuteNonQuery() should be removed it is not doing anything. adapter.Fill() should be executing the command and I do not know why you are not getting the expected response.
Related
I want to retrieve data from postgres db into textbox in C# without using grid.
Here is the running successful code by using grid which I had tried:
connection.Open();
NpgsqlCommand cmd = new NpgsqlCommand();
cmd.Connection = connection;
cmd.CommandText = "SELECT * FROM student_folio";
cmd.CommandType = CommandType.Text;
NpgsqlDataAdapter da = new NpgsqlDataAdapter(cmd);
DataTable dt = new DataTable();
da.Fill(dt);
cmd.Dispose();
connection.Close();
GridView1.DataSource = dt;
GridView1.DataBind();
I get error when build when I want to retrieve it into textbox:
"cannot apply indexing with [] to an expression of type 'NpgsqlDataAdapter'"
Here is my block of code:
connection.Open();
NpgsqlCommand cmd = new NpgsqlCommand();
cmd.Connection = connection;
cmd.CommandText = ("SELECT f_name FROM student_folio WHERE id = 1");
cmd.CommandType = CommandType.Text;
NpgsqlDataAdapter da = new NpgsqlDataAdapter(cmd);
txtFname.Text = da["f_name"].ToString();
cmd.ExecuteNonQuery();
cmd.Dispose();
connection.Close();
A DataAdapter is not an array of rows you can loop into.
Look at your first code block : you must fill a DataTable from your adapter and then read through the Rows property of this DataTable.
NpgsqlDataAdapter da = new NpgsqlDataAdapter(cmd);
DataTable dt = new DataTable();
da.Fill(dt);
if (dt.Rows.Count > 0)
{
txtFname.Text = dt.Rows[0]["f_name"].ToString();
}
You could also do this :
foreach (System.Data.DataRow row in dt.Rows)
{
txtFname.Text = row["f_name"].ToString();
}
And please, remove the cmd.ExecuteNonQuery(); line, it is useless here
try this . .
connection.Open();
NpgsqlCommand cmd = new NpgsqlCommand();
NpgsqlDataReader dr=null;
cmd.Connection = connection;
cmd.CommandText = ("SELECT f_name FROM student_folio WHERE id = 1");
cmd.CommandType = CommandType.Text;
dr=cmd.ExecuteReader();
while(dr.HasRows)
{
while(dr.Read())
{
txtFname.Text = da["f_name"].ToString();
}
}
connection.Close();
Please help when i insert a new data to the database it is not showing in the comboBox unless i restart the program. Is something missing from this ?
CmbSupp.Items.Clear();
con.Open();
Refresh();
SqlCommand cmd = con.CreateCommand();
cmd.CommandType = CommandType.Text;
cmd.CommandText = "select SupplierName from SuppTbl";
cmd.ExecuteNonQuery();
DataTable dt = new DataTable();
SqlDataAdapter dp = new SqlDataAdapter(cmd);
dp.Fill(dt);
foreach (DataRow dr in dt.Rows)
{
CmbSupp.Items.Add(dr["SupplierName"].ToString());
}
con.Close();
Thankyou in advance!
Change
CmbSupp.Items.Clear()
To CmbSupp.Items = null;
this is a small Bug,You have to set Null Value and Reset Data;
Try It;
You could do this:
DataTable dt = new DataTable();
private void RefreshData()
{
dt.Clear();
con.Open();
Refresh();
SqlCommand cmd = con.CreateCommand();
cmd.CommandType = CommandType.Text;
cmd.CommandText = "select SupplierName from SuppTbl";
cmd.ExecuteNonQuery();
SqlDataAdapter dp = new SqlDataAdapter(cmd);
dp.Fill(dt);
con.Close();
cmd.Dispose();
}
private void BindToComboBox()
{
CmbSupp.DataSource = dt;
CmbSupp.ValueMember = "SupplierName";
CmbSupp.DisplayMember = "SupplierName";
}
Ideally, you include the table's ID and put it in ValueMember property. You call the Bind ToComboBox once and just call RefreshData() when there's changes in the database. It should automatically update the contents of the combobox.
Hi i have Attendance and Departure System on mvc Using Ado.Net My Connection Name is (DBConnection) i have Two Method One For OnClick TimeIn and AND OTHER one for TimeOut , My DataBase Name LoginTime and My Table is Attendance I have Problem in onclick timein Btton check if row not exist in my Attendance table insert new row else show Message "You Already TimeIn"
public void Addtime(Attendance AddTim)
{
SqlCommand comm = new SqlCommand("select * from Attendance where UserID=#user", conn);
comm.Parameters.AddWithValue("#user", AddTim.UserID);
conn.Open();
var rd = comm.ExecuteReader();
bool sat = rd.Read();
conn.Close();
if (sat == true)
{
SqlCommand updCommand = new SqlCommand("UPDATE Attendance SET TimeIn=#timein WHERE UserID=#userid", conn);
updCommand.Parameters.AddWithValue("#userid", AddTim.UserID);
updCommand.Parameters.AddWithValue("#timein", DateTime.Now);
conn.Open();
int rowsUpdated = updCommand.ExecuteNonQuery();
var rdr = comm.ExecuteReader();
conn.Close();
}
else
{
SqlCommand insCommand = new SqlCommand("INSERT into Attendance (UserID,TimeIn) VALUES (#userid,#timein)", conn);
insCommand.Parameters.AddWithValue("#userid", AddTim.UserID);
insCommand.Parameters.AddWithValue("#timein", DateTime.Now);
conn.Open();
int rowsUpdated = insCommand.ExecuteNonQuery();
var rdr = comm.ExecuteReader();
conn.Close();
}
}
public void Addtimout(Attendance addtimout)
{
SqlCommand UpDCommand = new SqlCommand("UPDATE Attendance SET TimeOut=#timeout WHERE UserID=#userid", conn);
UpDCommand.Parameters.AddWithValue("#UserID", addtimout.UserID);
UpDCommand.Parameters.AddWithValue("#timeout", DateTime.Now);
conn.Open();
UpDCommand.ExecuteNonQuery();
conn.Close();
}
}
}
There is probably more going on then what I can deduce from your question and no real explanation of the error (if any) you are getting. If this is so please post the error or unexpected behavior, and the database schema would also be helpful
I did notice that you are doing multiple insert or update statements in that block, as you are executing each query twice; once as a NonQuery and again as a Reader.
int rowsUpdated = insCommand.ExecuteNonQuery();
var rdr = comm.ExecuteReader();
The original query to check doesn't look to great to me. If you simply want to check for a row count, you could use SELECT Count(*), and execute via ExecuteScalar(). This will remove the overhead of a Reader
public void Addtime(Attendance AddTim) {
SqlCommand comm = new SqlCommand("select Count(*) from Attendance where UserID=#user", conn);
comm.Parameters.AddWithValue("#user", AddTim.UserID);
conn.Open();
int uc = (int)comm.ExecuteScalar();
bool sat = (uc > 0);
conn.Close();
I have table consisting columns(....,....,....,BLOCK) in my database.
The BLOCK column has bit datatype(True,False).
When BLOCK column has False, the data should be fetched from the database.
When BLOCK column has True, the data should not be fetched resulting in throwing an error.
When I give the name of a particular person in textbox and click button, the above operation must be performed
my button click c# coding is...
protected void ImageButton5_Click(object sender, ImageClickEventArgs e)
{
string selectsql = "SELECT * FROM UserDetailsTwo";
using (SqlConnection con = new SqlConnection(#"Data Source=ENTERKEY001;Initial Catalog=ContactManagement;Integrated Security=True"))//DataBase Connection
{
SqlCommand selectCommand = new SqlCommand(selectsql, con);
con.Open();
SqlDataReader SelectReader = selectCommand.ExecuteReader();
while (SelectReader.Read())
{
Boolean BLOCK = Convert.ToBoolean(SelectReader["BLOCK"]);
if (BLOCK == false)
{
//con.Open();
SqlCommand cmd = con.CreateCommand();
cmd.CommandType = CommandType.StoredProcedure;
cmd.CommandText = "SearchUser";
cmd.Parameters.AddWithValue("#NAME", TextBox4.Text.Trim());
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataTable dt = new DataTable();
da.Fill(dt);
GridView1.DataSource = dt;
GridView1.DataBind();
con.Close();
}
else
{
Response.Write("Error");
}
}
SelectReader.Close();
}
}
You are trying to use an SQLDataReader like a DataAdapter.
SelectReader = selectCommand.ExecuteReader();
while (SelectReader.Read())
{
Int64 BLOCK = Convert.ToInt64(SelectReader["BLOCK"]);
if (BLOCK == false)
{
con.Open();
SqlCommand cmd = con.CreateCommand();
cmd.CommandType = CommandType.StoredProcedure;
cmd.CommandText = "SearchUser";
cmd.Parameters.AddWithValue("#NAME", TextBox4.Text.Trim());
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataTable dt = new DataTable();
da.Fill(dt);
GridView1.DataBind();
con.Close();
}
else
{
Response.Write("Error");
}
}
https://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqldatareader%28v=vs.110%29.aspx
I am passing sqlparameter in localize language (Persian) from c# but no rows retrieves. Database already collate for persioan_100_ci_ai and tables are collate database_default
SqlCommand cmd = new SqlCommand();
DataTable dt = new DataTable();
SqlDataReader dr = default(SqlDataReader);
dt.TableName = "temp";
try {
if (!(conn.State == ConnectionState.Closed))
conn.Close();
if (conn.State == ConnectionState.Closed)
conn.Open();
cmd.Connection = conn;
string qry = "Select * from users WHERE [Name]=#UserName AND [Pwd]=#Password";
cmd.commandtext = qry;
cmd.Parameters.Add("#UserName", SqlDbType.NVarChar, 50).Value = "ادمین";
cmd.Parameters.Add("#Password", SqlDbType.NVarChar, 50).Value = "ادمین";
dr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
if (dr.HasRows) {
dt.Load(dr);
}
return dt;
} catch (Exception ex) {
return null;
} finally {
dt = null;
cmd.Connection = null;
cmd.Parameters.Clear();
cmd.Dispose();
}
It works in SSMS
declare #UserName nvarchar(50) = 'ادمين'
declare #Password nvarchar(50)= 'ادمين'
select * from Users where [name]=#UserName and [Pwd] = #Password
It even works when I am embedding variables in query instead of parameter
SqlCommand cmd = new SqlCommand();
DataTable dt = new DataTable();
SqlDataReader dr = default(SqlDataReader);
string pLoginName = "ادمین";
string pPassword = "ادمین";
dt.TableName = "temp";
try {
if (!(conn.State == ConnectionState.Closed))
conn.Close();
if (conn.State == ConnectionState.Closed)
conn.Open();
cmd.Connection = conn;
string qry = "Select * from users WHERE [Name]='" + pLoginName + "' AND [Pwd]='" + pPassword + "'";
cmd.CommandText = qry;
dr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
if (dr.HasRows) {
dt.Load(dr);
}
return dt;
} catch (Exception ex) {
return null;
} finally {
dt = null;
cmd.Connection = null;
cmd.Parameters.Clear();
cmd.Dispose();
}
Cannot figure out where I am wrong.
Please, if any one can point out.
I don't have any problems, I add both values to my test database. Here is the sample code
// Code in BO logic method
string email = "ادمین";
string password = "ادمین";
SqlCommand cmd = new SqlCommand(#"SELECT * FROM Register WHERE Email=#Email AND Deleted=0 AND Password=#Pass");
cmd.Parameters.AddWithValue(#"Email", email.Trim());
cmd.Parameters.AddWithValue(#"Pass", password.Trim());
DataSet dst = Varmebaronen.AppCode.DA.SqlManager.GetDataSet(cmd);
//DataAccess Methods !
public static DataSet GetDataSet(SqlCommand cmd)
{
return GetDataSet(cmd, "Table");
}
public static DataSet GetDataSet(SqlCommand cmd, string defaultTable)
{
SqlConnection conn = GetSqlConnection(cmd);
try
{
DataSet resultDst = new DataSet();
using (SqlDataAdapter adapter = new SqlDataAdapter(cmd))
{
adapter.Fill(resultDst, defaultTable);
}
return resultDst;
}
catch
{
throw;
}
finally
{
conn.Close();
}
}
DataSet had one record, try to use AddWithValue. If again nothing happen the problem is not in the parameters !
P.S Don't use one static connection, application pool is your friend !
Try seperating out the parameter and value assignment like below:
// Create the parameter objects as specific as possible.
cmd.Parameters.Add("#UserName", System.Data.SqlDbType.NVarChar, 50);
cmd.Parameters.Add("#Password", System.Data.SqlDbType.NVarChar, 50);
// Add the parameter values. Validation should have already happened.
cmd.Parameters["#UserName"].Value = "ادمین";
cmd.Parameters["#Password"].Value = "ادمین";
Try to use this:
cmd.Parameters.Add(new SqlParameter("#Password", "ادمین"));
EDIT:
Lets try a different way. If you're up for some re-coding. I will post an example from an old college project that works. It's essentially the same concept. May not be the best way but it works...
I used a DataAdapter, a DataSet, and a GridView control on an .aspx page. You tagged ASP.net, but I am not sure what you're trying to use to display the data.
string selectsql2 = "SELECT * FROM [dbo].Event_View WHERE (EventName LIKE '%' + #EventName + '%')";
SqlConnection connect2 = new SqlConnection(connectionstring2);
SqlCommand cmd = new SqlCommand(selectsql2, connect2);
SqlParameter pm = new SqlParameter("#EventName", txtEvents.Text);
cmd.Parameters.Add(pm);
SqlDataAdapter adapter = new SqlDataAdapter(cmd);
DataSet ds2 = new DataSet();
adapter.Fill(ds2);
gvEvents.DataSource = ds2;
gvEvents.DataBind();