ok so i have a text box and a button where i will enter a number and press the button. I then want a message box to display if the value has been found or not.
I put all my functions in a model class then call them for the GUI part.
heres what i tried so the sql function (ticket is the name of the table and ID is the value im trying to find):
public void rebateslip(int ticketID)
{
SqlCommand myCommand = new SqlCommand("SELECT ID FROM ticket WHERE ID = #ticketID", con);
SqlDataAdapter sqlDa = new SqlDataAdapter(myCommand);
myCommand.Parameters.AddWithValue("#ID", ticketID);
}
and than for the button event handler i have this:
private void buttonPrintRebateSlip_Click(object sender, EventArgs e)
{
if (textBoxRebateSlip = model.rebateslip(ticketID)
{
MessageBox.Show("Found ticket");
}
else
{
MessageBox.Show("Ticket not in database");
}
}
but it says ticketID does not exist
Your parameter is named ticketID, not ID
So, you should change to:
myCommand.Parameters.AddWithValue("#ticketID", ticketID);
you should change your model.rebateslip method so that it return a bool, and execute your command, then it should look more or less like this: (don't have the SqlCommand methods in mind, nor the reader's ones, but according to my memory it looks like this)
public bool rebateslip(int ticketID)
{
SqlCommand myCommand = new SqlCommand("SELECT ID FROM ticket WHERE ID = #ticketID", con);
SqlDataAdapter sqlDa = new SqlDataAdapter(myCommand);
myCommand.Parameters.AddWithValue("#ticketID", ticketID);
var reader = myCommand.Execute();
return reader.HasRows;
}
then you should do something like #Ezekiel said in his answer:
int id;
if (!int.TryParse(textBoxRebateSlip.Text, out id)) return;
if (model.rebateslip(id))
...
if (textBoxRebateSlip == model.rebateslip(ticketID)
The If statement is not correct, you are missing a closing paren and the comparison is not valid either. Use == for comparison. Furthermore, ticketID variable is not initialized anywhere. From your description it sounds like you are getting it from the textbox? If so it should be something like this:
int id = Convert.ToInt32(textBoxRebateSlip .Text);
if (model.rebateslip(ticketID) == id)
...
Another thing I noticed, you are not executing the sql command anywhere?
Also, the rebateslip method has return type void, so it will not work.
With all these errors, this code would not even compile.
Related
I wrote some code for search page as follows
I declared variables in above page load as follows
static String strsql = "";
in page load
if(!isPostback)
{
if(session["username"] != null)
{
loadprofiles(); // calling loadprofiles method
bindlist();//loading gridview data
}
}
now loadprofiles method wrote as follows
protected void loadprofiles()
{
strsql = "select * from admintable where userid = '"+session["username"].Tostring()+"'";
}
now bindlist method is as follows
private void bindlist()
{
SqlCommand comm1 = new SqlCommand(strsql, connection);
//and some code for binding data to gridview
}
the problem is while two different users are login into this page from two different computers the user getting the data from second login persions
please help me to solve this problem...
thanks in advance
I was having Session issue for multiple tabs in a single browser.
In Default.aspx/Index.aspx write below code to generate a Unique session Id's.
if (Page.IsPostBack == false) //If page loads for the first time
{
ViewState["_PageID"] = Guid.NewGuid();
}
To store any variable in session Use the following lines:
Session[ViewState["_PageID"].ToString() + "username"] = "testuserName";
To access anything stored based on the Session Id:
string userNameInSession = Session[ViewState["_PageID"].ToString() + "username"] as string;
You cannot declare strsql as static since it will store value for all users - user1 will have access to the user2 strsql value. You have to remember that static is a member of a type, not an instance - it will be accessible for all users until AppDomain is unloaded.
In my opinion you shouldn't store SQL query in a variable(it seems unnecessary since session is accessible everywhere in your code).
I'd change your code to the
private void bindlist()
{
SqlCommand comm1 = new SqlCommand("select * from admintable where userid = '"+session["username"].Tostring()+"'", connection);
//and some code for binding data to gridview
}
EDIT:
Since you want to reuse query, you can return it from loadprofiles() method like follows:
protected string loadprofiles()
{
strsql = "select * from admintable where userid = '"+session["username"].Tostring()+"'";
// Do your logic there...
return strsql;
}
and use it:
if(!isPostback)
{
if(session["username"] != null)
{
var strsql = loadprofiles(); // calling loadprofiles method
bindlist(strsql);//loading gridview data
}
}
I believe you get the point.
So basically i have an SQL server. I have 4 columns. I will design this table here:
varchar varchar int varchar
account password gmlevel pics
test test 3 url
First, my method checks that the entered account and password is equal (login query).
Then i want to check that the 'test' account how high acces (gmlevel) has to this, then save it to a variable.
It's need to be two query. But the gmlevel record is a very important to my program, and it's not working at all.
Here is my connection:
private void gmset ()
{
if (loggedin == true) {
try
{
using (var con2 = new SqlConnection())
{
string user = login.felhasz;
string query2 = "SELECT * FROM accounts WHERE account=#acc";
con2.ConnectionString = "connection string";
con2.Open();
var cm2 = new SqlCommand(query2, con2);
cm2.Parameters.AddWithValue("#acc", user);
SqlDataReader dr2 = cm2.ExecuteReader();
while (dr2.HasRows)
{
MessageBox.Show("ASD");
}
}
}
catch (Exception exe)
{
MessageBox.Show(exe.Message);
}
}
else {
MessageBox.Show("Failed!");
}
This code doesn't hold anything that you can use for getting the GMLevel. I've tried many things, i've been looking for answer now a day ago, still nothing.
/Sorry for multiple questioning but i'm getting further and closer to solution
You can call Read() method to get the gmlevel.
Try This:
int GameLevel;
while (dr2.Read())
{
int.TryParse(dr2["gmlevel"].ToString(),out GameLevel);
MessageBox.Show("ASD");
}
EDIT: i suspect that control is not entering the while loop.
Try This: Replace/Comment your while loop with following if-else block and see the results
if(dr2.Read())
{
MessageBox.Show("Record Found");
}
else
{
MessageBox.Show("Record Not Found!!!");
}
while (dr2.HasRows)
{
Object[] output = new Object[dr2.FieldCount];
dr2.GetValues(output);
MessageBox.Show(output[2].ToString());
}
I'm trying to upgrade the db from users' input, but it doesn't work...
I'm using this:
protected void Button1_Click(object sender, EventArgs e)
{
SqlConnection con = new SqlConnection(strcon);
SqlCommand cmd = new SqlCommand();
SqlCommand ncmd = new SqlCommand("Update Utenti Set Nome = #vnome where [Indirizzo E-Mail]=#vem", con);
ncmd.Parameters.AddWithValue("#vem", Session["[Indirizzo E-Mail]"].ToString());
ncmd.Parameters.AddWithValue("#vnome", TextBox2.Text);
ncmd.Connection = con;
con.Open();
ncmd.ExecuteNonQuery();
con.Close();
Label2.Text = "Dati aggiornati con successo!";
Response.Redirect("~/ModificaDati.aspx");
}
When I click on the button it show me the Label2 text, but in the database the "Nome" is not changed, why?
Thanks before for the answers ^^
I would change your method as below
if (Session["[Indirizzo E-Mail]"] != null &&
!string.IsNullOrEmpty(Session["[Indirizzo E-Mail]"].ToString()) &&
!string.IsNullOrEmpty(TextBox2.Text))
{
string vem = Session["[Indirizzo E-Mail]"].ToString();
using (var con = new SqlConnection(strcon))
using (var ncmd = new SqlCommand("Update Utenti Set Nome = #vnome where [Indirizzo E-Mail]=#vem", con))
{
con.Open();
ncmd.Parameters.AddWithValue("#vem", vem);
ncmd.Parameters.AddWithValue("#vnome", TextBox2.Text);
int rows = ncmd.ExecuteNonQuery();
Label2.Text = rows + " Dati aggiornati con successo!";
}
}
Response.Redirect("~/ModificaDati.aspx");
Added input validation, session values can be null, better to check before you update database
when you create SqlCommand you can give the connection, no need to set it again
make sure your SQL is valid
use using statements for disposable objects like SqlConnection, SqlCommand
Your code looks ok. Just make sure you check if SQL is correct as Damith already suggested.
Another thing I’s recommend is additionally validating your parameters for data type correctness before executing the query.
Using this approach you’ll probably avoid a lot of unnecessary exceptions and also be able to provide more user friendly messages. Of course this only applies if user input is non text type
//Data Type verification
DateTime tmp;
if (!DateTime.TryParse(Label2.Text.Trim(), out tmp))
{
//Show error message that this is not a correct data type
}
Open your connection first
con.Open();
ncmd.Connection = con;
Hope it helps
I want to ask more to show data from SQL Server to WinForm using a datagrid.
I've been creating a datagrid and the stored procedure to show data is
ALTER PROC [dbo].[SP_GetData]
AS
SELECT nama , nim
FROM tabledata
and I've created the function to access the database and the stored procedure in C#
string Sp_Name = "dbo.SP_GetData";
SqlConnection SqlCon = new SqlConnection("Integrated Security=SSPI;Persist Security Info=False;Initial Catalog=DBMahasiswa;Data Source=.");
SqlCon.Open();
SqlCommand SqlCom = new SqlCommand(Sp_Name , SqlCon);
SqlCom.CommandType = CommandType.StoredProcedure;
List<mahasiswaData> listMahasiswa = new List<mahasiswaData>();
using (SqlDataReader sqlDataReader = SqlCom.ExecuteReader())
{
if (sqlDataReader.HasRows)
{
while (sqlDataReader.Read())
{
mahasiswaData DataMhs = new mahasiswaData();
DataMhs.Nama = sqlDataReader["Name"].ToString();
DataMhs.Umur = Convert.ToInt32(sqlDataReader["Age"]);
listMahasiswa.Add(DataMhs);
}
}
}
SqlCon.Close();
return listMahasiswa;
and finally, in the show button I add this code
dgvmahasiswa.DataSource = new MahasiswaDB().LoadMahasiswa();
Could somebody tell me where the fault is or the alternatives one?
Thank You So Much! :D
Some things to think about:
At the moment, if your code runs into exceptions, you'll leave a
SqlConnection hanging around; you've used the using pattern for your
SqlDataReader; you should extend it to all of your disposable
objects.
You are swallowing exceptions; if your query fails, the connection
cannot be made, or something else happens, you'll never really know - your function will just return null.
Is it possible for name or age to be null? Age to be non-numeric?
There's no test for any unexpected values, which you'll also never
know about.
If you don't have any records, you'll return an empty list. Is this
desired? Or would you prefer to know there were no records?
You might prefer to look at something like this:
public List<mahasiswaData> GetData(){
List<mahasiswaData> gridData = new List<mahasiswaData>();
try{
using(SqlConnection conn = new SqlConnection("Integrated Security=SSPI;Persist Security Info=False;Initial Catalog=DBMahasiswa;Data Source=."))
{
using(SqlCommand command = new SqlCommand())
{
command.Connection = conn;
command.CommandType = CommandType.StoredProcedure;
command.Text = "dbo.SP_GetData";
using(SqlDataReader reader = command.ExecuteReader())
{
if(reader.HasRows){
while(reader.Read())
{
object rawName = reader.GetValue(reader.GetOrdinal("Name"));
object rawAge = reader.GetValue(reader.GetOrdinal("Age"));
if(rawName == DBNull.Value || rawAge == DBNull.Value)
{
//Use logging to indicate name or age is null and continue onto the next record
continue;
}
//Use the object intializer syntax to create a mahasiswaData object inline for simplicity
gridData.Add(new mahasiswaData()
{
Nama = Convert.ToString(rawName),
Umur = Convert.ToInt32(rawAge)
});
}
}
else{
//Use logging or similar to record that there are no rows. You may also want to raise an exception if this is important.
}
}
}
}
}
catch(Exception e)
{
//Use your favourite logging implementation here to record the error. Many projects use log4Net
throw; //Throw the error - display and explain to the end user or caller that something has gone wrong!
}
return gridData;
}
Note that if you are sure that age or name will never be null then you can simplify the middle section:
while (reader.Read())
{
//Use the object intializer syntax to create a mahasiswaData object inline for simplicity
gridData.Add(new mahasiswaData()
{
Nama = reader.GetString(reader.GetOrdinal("Name")),
Umur = reader.GetInt32(reader.GetOrdinal("Age"))
});
}
Sorry in advance im going to try and explain this as best as possible....
I have 2 asp.net pages one named membermaster and the second named memberdetails. I created a class library which contains 2 functions
My first function returns a list depending on the search result...
I added a linkbutton to the gridviews first column which when clicked it passes through querystring the membershipgen. What i wanted to do is for my second function i created this
public DataTable GetMembers(int MEMBERSHIPGEN)
{
DataTable table = null;
SqlConnection con = null;
SqlCommand cmd = null;
SqlDataAdapter ad = null;
SqlParameter prm = null;
try
{
table = new DataTable();
using (con = new SqlConnection(connectionString))
{
using (cmd = new SqlCommand("usp_getmemberdetail", con))
{
using (ad = new SqlDataAdapter(cmd))
{
prm = new SqlParameter("#MEMBERSHIPGEN", SqlDbType.Int);
prm.Value = MEMBERSHIPGEN;
cmd.Parameters.Add(prm);
ad.Fill(table);
}
}
}
}
catch (Exception ex)
{
//write your exception code here
}
return table;
}
In the attempt to try and send the membershipgen to this and it return the results. But once i compile the DLL and add it to my project I am not sure how i would reference this function to populate individual textboxes and labels with the information.
What I am trying to do is when a user clicks the viewdetails button on the gridview I can then use that membershipgen that I passed through querystring to populate the page through a stored procedure but the smarts would be stored in a DLL.
You probably want your method to return a value. Currently the return type is void, so the values it populates internally just go away when the call stack leaves the method. It sounds like you want something like this:
public DataTable GetMembers(int MEMBERSHIPGEN)
Then, in your method, after you've populated the DataTable and exited the using blocks, you'd do something like this:
return table;
This would return the DataTable to whatever called the method. So your page would have something like this:
DataTable table = GetMembers(membershipgen);
So the page would be responsible for:
Get the membershipgen value from the input (query string)
Call the method and get the result of the method
Display the result from the method (bind to a grid? or whatever you're doing to display the data)
And the method is responsible for:
Interact with the database
This is a good first step toward the overall goal of "separation of concerns" which is a very good thing to do. You can continue down this path by always asking yourself what each method, class, etc. should be responsible for. For example, your GetMembers method should also be responsible for ensuring that the value passed to it is valid, or that the value returned from it is not null.
You need to change GetMembers to return data instead of void. If you want to use DataTables, you can just modify your code to this:
public DataTable GetMembers(int MEMBERSHIPGEN)
{
DataTable table = new DataTable();
SqlConnection con = new SqlConnection(connectionString);
using (SqlCommand cmd = new SqlCommand("usp_getmemberdetail", con))
{
using (SqlDataAdapter ad = new SqlDataAdapter(cmd))
{
SqlParameter prm = new SqlParameter("#MEMBERSHIPGEN", SqlDbType.Int);
prm.Value = MEMBERSHIPGEN;
cmd.Parameters.Add(prm);
ad.Fill(table);
return table;
}
Then in your Page_Load it might be something like this (more robust than this hopefully):
{
DataTable table = yourDll.GetMembers(Convert.ToInt32(Request.QueryString["membership"]));
label1.Text = Convert.ToString(table.rows[0]["Name"]);
}
One way to go might be to construct the button so that it navigates to a url along the lines of:
http://localhost/DetailPage.aspx?membershipgen=4
Then in the load of the DetailPage.aspx:
Page_Load(Object sender, EventArgs e)
{
if (!this.IsPostback)
{
int membershipgen;
if (int.TryParse(Request.QueryString["membershipgen"], out membershipgen)
{
//Get the data (replace DataAccess with the name of your data access class).
//Also, you probably want to change GetMembers so it returns the data.
DataTable table = DataAccess.GetMembers(membershipgen);
//TODO: Display the results
}
}
else
{
//Display an error
}
}