i have problems filling my checkboxlist from a sql in c#. The list is empty when it have been loaded.
I know it would probably be easier with a connection to web.config, but i have decieded not to have web.config in this project. It would be helpfull if anyone could see what i have done wrong.
This is my code:
string connetionString = "Data Source=[DATA-SOURCE];Initial Catalog=[CATALOG];User ID=[USER-ID];Password=[PASSWORD]";
SqlConnection cnn = new SqlConnection(connetionString);
using (SqlCommand cmd = new SqlCommand())
{
cmd.CommandText = "SELECT ModuleID, ModuleName, InternalName, Active FROM dbo.Zodiac_System_Modules WHERE Active = 1 ORDER BY ModuleName ASC";
cmd.Connection = cnn;
cnn.Open();
using (SqlDataReader sdr = cmd.ExecuteReader())
{
while (sdr.Read())
{
ListItem item = new ListItem();
item.Text = sdr["ModuleName"].ToString();
item.Value = sdr["InternalName"].ToString();
chkModules.Items.Add(item);
}
}
cnn.Close();
}
You Are Missing CommandType This:
cmd.CommandType=CommandType.Text;
Related
I would like to get some help : I can't get values form SQL Database to WPF textbox.
I tried by myself many codes that didn't worked, and this one looks fine but ".ToString" argument is wrong.
What should i put instead ?
using (SqlConnection con = new SqlConnection(MyConnString))
{
SqlCommand sqlCmd = new SqlCommand("SELECT DATE_A FROM Donnees_Accueil", con);
con.Open();
SqlDataReader sqlReader = sqlCmd.ExecuteReader();
while (sqlReader.Read())
{
hourA.Text = sqlReader["Date_A"].ToString;
}
sqlReader.Close();
}
Thank you in advance,
Zancrew.
Well, ToString() is a method, not property, that's why () is required; if you want to concat all the records:
using (SqlConnection con = new SqlConnection(MyConnString))
{
con.Open();
using (SqlCommand sqlCmd = new SqlCommand("SELECT DATE_A FROM Donnees_Accueil", con))
{
using (SqlDataReader sqlReader = sqlCmd.ExecuteReader())
{
StringBuilder sb = new StringBuilder();
while (sqlReader.Read())
{
sb.Append(Convert.ToString(sqlReader["Date_A"]));
}
hourA.Text = sb.ToString();
}
}
}
If you want to get the 1st record only:
using (SqlConnection con = new SqlConnection(MyConnString))
{
con.Open();
using (SqlCommand sqlCmd = new SqlCommand("SELECT DATE_A FROM Donnees_Accueil", con))
{
using (SqlDataReader sqlReader = sqlCmd.ExecuteReader())
{
if (sqlReader.Read())
hourA.Text = Convert.ToString(sqlReader["Date_A"]);
else
hourA.Text = "";
}
}
}
I tried to get data in a drop down list and it's not working. I don't understand what's the problem.
string connString = #" Data Source=(LocalDB)\v11.0;AttachDbFilename='C:\Users\oshri\Documents\Stock scores.mdf';Integrated Security=True;Connect Timeout=30";
string queryLecturer = "select name_student from student";
SqlConnection conn = new SqlConnection(connString);
//SqlCommand cmdL = new SqlCommand(queryLecturer, conn);
conn.Open();
//SqlCommand SQLCommand = new SqlCommand();
//cmdL.CommandType = CommandType.Text;
//SQLCommand.CommandText = queryLecturer;
//conn.Close();
SqlDataAdapter adapter = new SqlDataAdapter(queryLecturer, conn);
adapter.Fill(subjects);
DropDownListID.DataSource = subjects;
DropDownListID.DataBind();
DropDownListID.DataBind();
conn.Close();
You are assigning a DataSet containing DataRowView items to your drop down. Your drop down (is it a System.Windows.Forms.ComboBox?) is not smart enough to extract the real values from this DataSet. Instead, use a SqlDataReader to read your string values and add them to a list that you can use as data source for your drop down.
string connString = #"Data Source=...";
string queryLecturer = "select name_student from student";
using (var conn = new SqlConnection(connString))
using (var cmd = new SqlCommand(queryLecturer)) {
conn.Open();
using (SqlDataReader reader = cmd.ExecuteReader()) {
var list = new List<string>();
while (reader.Read()) {
list.Add(reader.GetString(0)); // 0 is the column index.
}
DropDownListID.DataSource = list;
}
}
The using statements automatically close the connection and dispose resources at the end of the statement blocks. They do so even if the statement blocks are left prematurely because of an exception or because of a break or return statement.
Im trying to add items in the comboBox (cmbInstructor) namely the last names (instructorLN) however, my code does not seem to work. Any ideas on where I went wrong?
private void cmbInstructor_SelectedIndexChanged(object sender, EventArgs e)
{
MySqlConnection conn = new MySqlConnection(mycon);
MySqlCommand cmd = new MySqlCommand("SELECT * FROM instructor WHERE instructorType ='" + labelClass.Text + "'", conn);
string instructorLN = "";
conn.Open();
MySqlDataReader myReader = null;
myReader = cmd.ExecuteReader();
while (myReader.Read())
{
instructorLN = myReader["instructorLN"].ToString();
}
cmbInstructor.Items.Add(instructorLN);
}
As far as I can see, you are adding only last value that your SELECT returns.
Move your
cmbInstructor.Items.Add(instructorLN);
line into to the while statement as;
while (myReader.Read())
{
cmbInstructor.Items.Add(myReader["instructorLN"].ToString());
}
By the way, you should always use parameterized queries. This kind of string concatenations are open for SQL Injection attacks.
Also use using statement to dispose your connection and command and reader automatically.
using(var conn = new MySqlConnection(mycon))
using(var cmd = conn.CreateCommand())
{
cmd.CommandText = "SELECT * FROM instructor WHERE instructorType = #type";
cmd.Parameters.Add("#type", labelClass.Text);
conn.Open();
using(var myReader = cmd.ExecuteReader())
{
while (myReader.Read())
{
cmbInstructor.Items.Add(myReader["instructorLN"].ToString());
}
}
}
protected void Page_Load(object sender, EventArgs e)
{
SqlConnection con = new SqlConnection(#"Data Source=.\SQLEXPRESS;AttachDbFilename=D:\ExportPagetoPDFinASP.Net\App_Data\abcc.mdf;Integrated Security=True;User Instance=True");
con.Open();
SqlCommand cmd = new SqlCommand();
cmd.CommandText = "SELECT * FROM cookbook";
cmd.Connection = con;
cmd.ExecuteReader();
}
Not able to fetch data. i don't know what is wrong.
ExecuteReader would return you a DataReader, you need to iterate it and get rows from your command.
You can also use a DataTable to fill the rows from DataReader like:
DataTable dt = new DataTable();
dt.Load(cmd.ExecuteReader());
You can have the following code:
using (SqlConnection con = new SqlConnection(#"Data Source=.\SQLEXPRESS;AttachDbFilename=D:\ExportPagetoPDFinASP.Net\App_Data\abcc.mdf;Integrated Security=True;User Instance=True"))
{
con.Open();
using (SqlCommand cmd = new SqlCommand())
{
cmd.CommandText = "SELECT * FROM cookbook";
cmd.Connection = con;
DataTable dt = new DataTable();
dt.Load(cmd.ExecuteReader());
}
}
Consider using using statement with your Connection and Command objects.
You can iterate rows returned from DataReader like:
SqlDataReader reader = cmd.ExecuteReader();
while (reader.Read())
{
Console.WriteLine(String.Format("{0}", reader[0])); //prints first column
}
public string Log(int userResult)
{
string result = "result saved";
using (var conn = new SqlConnection("Data Source=XXXX;InitialCatalog=XXXX;Integrated Security=True"))
{
using (var cmd = new SqlCommand())
{
cmd.CommandText = "dbo.setCalculatorResult";
cmd.CommandType = CommandType.StoredProcedure;
cmd.Connection = conn;
cmd.Parameters.AddWithValue("RESULT", userResult);
if (conn.State != ConnectionState.Open)
conn.Open();
int rowCount = cmd.ExecuteNonQuery();
if (rowCount == 0)
result = "there was an error";
}
}
return result;
}
and also consider using procs
It's easy to bind a data source to something like a gridview or repeater, but how would I do it with a label? Heres the sql connection that I want to modify. By the way, I don't need 2 way binding.
public void Sql_Connection(string queryString)
{
SqlConnection conn = new SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings["RBConnectionString"].ConnectionString);
SqlCommand cmd = new SqlCommand(queryString, conn);
conn.Open();
cmd.ExecuteNonQuery();
conn.Close();
}
The query I'm using:
SELECT Description FROM RbSpecials WHERE Active=1
public string SqlConnection(string queryString)
{
using (var conn = new SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings["RBConnectionString"].ConnectionString))
using (var cmd = conn.CreateCommand())
{
conn.Open();
cmd.CommandText = queryString;
using (var reader = cmd.ExecuteReader())
{
while (reader.Read())
{
// This will return the first result
// but there might be other
return reader.GetString(0);
}
}
return null;
}
}
This will also ensure that in case of exception all disposable objects are disposed and will properly return the SQLConnection to the connection pool in order to be reused.
And finally assign the Text property of the label:
lblTest.Text = SqlConnection("SELECT Description FROM RbSpecials WHERE Active=1");
use ExecuteReader rather than ExecuteNonQuery
public void Sql_Connection(string queryString)
{
using(SqlConnection conn = new SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings"RBConnectionString"].ConnectionString))
{
using(SqlCommand cmd = new SqlCommand(queryString, conn))
{
conn.Open();
using(SqlDataReader rdr = cmd.ExecuteReader())
{
while(rdr.Read())
{
lblDescription.Text = rdr.GetString(0);
}
}
}
}
}
using (SqlConnection con = new SqlConnection(Connection_String))
{
SqlCommand cmd = new SqlCommand("select * from Customers", con);
cmd.CommandType = CommandType.StoredProcedure;
SqlDataReader adpt = cmd.ExecureReader();
if(rdr.Read())
{
lblName.Text = rdr[0].ToString();
}
}