private void btn_Update_Click(object sender, EventArgs e)
{
con.Open();
SqlCommand cmd = con.CreateCommand();
cmd.CommandType = CommandType.Text;
cmd.CommandText = "update MyWeight set Weight='" + txt_Weight.Text + "'where Name='" + txt_Name.Text + "'";
string a = (string)cmd.ExecuteScalar();
con.Close();
if (a != null)
{
cmd.ExecuteNonQuery();
con.Close();
display_data();
MessageBox.Show("Weight updated successfuly!!!");
}
else
{
con.Close();
display_data();
MessageBox.Show("Not updated!!!");
}
}
I tried to update the weight into the database, but the database keeps saying that it is not updated.
Try like this:
bool updated;
con.Open();
using (SqlCommand cmd = con.CreateCommand())
{
cmd.CommandType = CommandType.Text;
cmd.CommandText = "update MyWeight set Weight=#Weight where Name=#Name";
cmd.Parameters.Add(new SqlParameter("Weight", txt_Weight.Text));
cmd.Parameters.Add(new SqlParameter("Name", txt_Name.Text));
updated = (cmd.ExecuteNonQuery() > 1);
con.Close();
}
if (updated)
{
display_data();
MessageBox.Show("Weight updated successfuly!!!");
}
else
{
display_data();
MessageBox.Show("Not updated!!!");
}
It makes more sense to use ExecuteNonQuery for update operations in general because you don't expect any results.
Have you checked the table to see if it did update the row?
Why are you executing the same command with ExecuteNonQuery inside the if statement?
Related
Button click when workorder exist to update the datatable does not change anything in the datatable but when the workorder does not exist it will insert data into the datatable. Does anyone know where i gone wrong? I have changed the update statement from my other post(Syntax error in update using C# inputting data into an existing row) when this problem(button click dont change anything) appears
private void save_care_Click(object sender, EventArgs e)
{
if (textBox2.Text=="")
MessageBox.Show("No data, Please scan workorder");
else
{
//Checking if workorder exist in database
connection.Open();
OleDbCommand checkrecord = new OleDbCommand("SELECT COUNT(*) FROM [c# barcode] WHERE ([Workorder] = #workorder)", connection);
checkrecord.Parameters.AddWithValue("#workorder", textBox2.Text);
int recordexist = (int)checkrecord.ExecuteScalar();
if (recordexist > 0)
{
//add data if it exist
string cmdText = "UPDATE [c# barcode] SET [Close from care] =#Close,[Name care] =#name WHERE[Workorder] = #workorder"; ;
using (OleDbCommand cmd = new OleDbCommand(cmdText, connection))
{
cmd.Parameters.AddWithValue("#workorder", textBox2.Text);
cmd.Parameters.AddWithValue("#Close", DateTime.Now.ToString("d/M/yyyy"));
cmd.Parameters.AddWithValue("#name", label4.Text);
cmd.ExecuteNonQuery();
textBox2.Clear();
connection.Close();
}
connection.Close();
}
else
{
//inserting workorder if it does not exist
string cmdText = "INSERT INTO [c# barcode] ([Workorder],[Close from care],[Name care]) VALUES (#workorder,#Close,#name)";
using (OleDbCommand cmd = new OleDbCommand(cmdText, connection))
{
cmd.Parameters.AddWithValue("#workorder", textBox2.Text);
cmd.Parameters.AddWithValue("#Close", DateTime.Now.ToString("d/M/yyyy"));
cmd.Parameters.AddWithValue("#name", label4.Text);
if (cmd.ExecuteNonQuery() > 0)
{
textBox2.Clear();
MessageBox.Show("Insert succesful, workorder has not been handedover, Please Check");
}
else
{
textBox2.Clear();
MessageBox.Show("Please rescan");
connection.Close();
}
connection.Close();
}
}
}
}
string cmdText = "UPDATE [c# barcode] SET [Close from care] =#Close,[Name care] =#name WHERE[Workorder] = #workorder"; ;
First check the double semicolon at this string doesn't the compiler complain?
I am inserting data in the textbox1 and dropdown1 but the data is only saved in the query which is written at the second position"i.e in this case c_name". C_name is either empty or inserts null values.
protected void Button1_Click(object sender, EventArgs e)
{
con.Open();
MySqlCommand cmd = con.CreateCommand();
cmd.CommandType = CommandType.Text;
cmd.CommandText = "insert into market (m_name) values ('" + TextBox1.Text + "')";
cmd.CommandText = "insert into city (c_name) values('" + DropDownList1.SelectedValue + "')";
if (DropDownList1.SelectedValue == "-1")
{
Response.Write("Please select a city");
}
cmd.ExecuteNonQuery();
con.Close();
}
You should cmd.ExecuteNonQuery() after the first cmd.CommandText and then you have to do the same for your second cmd.CommandText, and both query will perform their actions.
protected void Button1_Click(object sender, EventArgs e)
{
if (DropDownList1.SelectedValue == "-1")
{
Response.Write("Please select a city");
return; // Must return don't execute after 'if' part or use 'else' there
}
con.Open();
MySqlCommand cmd = con.CreateCommand();
cmd.CommandType = CommandType.Text;
cmd.CommandText = "insert into market (m_name) values ('" + TextBox1.Text + "')";
cmd.ExecuteNonQuery(); // First insert executed here
cmd.CommandText = "insert into city (c_name) values('" + DropDownList1.SelectedValue + "')";
cmd.ExecuteNonQuery(); // Second insert executed here
con.Close();
}
I am currently trying delete my advertisement. But instead of deleting it from database I just want to set the status from 1 ( which means active ) to 0 (which means inactive). I have tried to use query UPDATE. But I do not know the format. My current code is
protected void btnDelete_Click(object sender, EventArgs e)
{
if (sqlCon.State == ConnectionState.Closed)
sqlCon.Open();
SqlCommand sqlCmd = new SqlCommand("DeleteImage", sqlCon);
sqlCmd.CommandType = CommandType.StoredProcedure;
sqlCmd.Parameters.AddWithValue("AdvID", Convert.ToInt32(hfContactID.Value));
sqlCmd.ExecuteNonQuery();
sqlCon.Close();
Clear();
FillGridView();
LitMsg.Text = "Deleted Successfully";
ButSave.Enabled = true;
Image1.Visible = false;
}
and I believe that Delete query does not change my status to 0 so my update query is something like this.
protected void btnUpdate_Click(object sender, EventArgs e)
{
if (FileImgsave.HasFile == true)
{
string imgfile = Path.GetFileName(FileImgsave.PostedFile.FileName);
//FileImgsave.SaveAs("Images/" + imgfile);
FileImgsave.SaveAs(Server.MapPath("~/Images/" + imgfile));
sqlCon.Open();
SqlCommand cmd = sqlCon.CreateCommand();
cmd.CommandType = CommandType.Text;
cmd.CommandText = "UPDATE Advertisement SET Item=#item,ImgPath=#image,Name=#name Where AdvID='" + AdsTb.Text + "'";
cmd.Parameters.AddWithValue("#name", nameTb.Text);
cmd.Parameters.AddWithValue("#item", imgfile);
cmd.Parameters.AddWithValue("#image", "~/Images/" + imgfile);
cmd.ExecuteNonQuery();
sqlCon.Close();
FillGridView();
LitMsg.Text = "Update successfully!";
Clear();
}
Below is my delete query
ALTER PROC [dbo].[DeleteImage]
#AdvID int
AS
BEGIN
DELETE FROM Advertisement
WHERE AdvID = #AdvID
END
You forgot to Update the Status
cmd.CommandText = "UPDATE Advertisement SET Status=0, Item=#item,ImgPath=#image,Name=#name Where AdvID='" + AdsTb.Text + "'";
Status=0
I am finding error of No value given for one or required parameter C# update query where ever i try to update my c# access data base here is the code...
hope somebody will be of my assistant..
private void updatebutton_Click(object sender, EventArgs e)
{
try
{
con.Open();
OleDbCommand cmd = new OleDbCommand();
cmd.Connection = con;
string query = "update Emplyeedata set [ID]='" + midbox.Text + "',[Name]='" + mnamebox.Text + "',[Deisgnation]='" + mdesbox.Text + "',[Leave]='" + mleavebox.Text + "'Where [Name]='"+mnamebox.Text+"'";
cmd.CommandText = query;
cmd.ExecuteNonQuery();
con.Close();
cb();
MessageBox.Show("Updated", "Message", MessageBoxButtons.OK, MessageBoxIcon.Information);
}
catch
{
MessageBox.Show("Error", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
}
}
as a bit more improvement you can try like this, and if you can post the full error information.
private void updatebutton_Click()
{
using (OleDbConnection con = new OleDbConnection("Define your Connection String here"))
{
string query = #"UPDATE Emplyeedata
SET [id] = #ID
,[Name] = #Name
,[Deisgnation] = #Deisgnation
,[Leave] = #Leave
WHERE [Name] = #Name";
using (OleDbCommand cmd = new OleDbCommand(query, con) { CommandType = CommandType.Text })
{
cmd.Parameters.AddWithValue("#ID", midbox.Text);
cmd.Parameters.AddWithValue("#Name", mnamebox.Text);
cmd.Parameters.AddWithValue("#Deisgnation", mdesbox.Text);
cmd.Parameters.AddWithValue("#Leave", mleavebox.Text);
cmd.Parameters.AddWithValue("#Name", mnamebox.Text);
con.Open();
cmd.ExecuteNonQuery();
}
con.Close();
}
}
(this is a really unstructured way and please follow the SOLID Principle/s)
I'm pretty sure that the Sql Syntax is right since it's a legit query.
However i've never stumbled on this issue before.
private void button1_Click(object sender, EventArgs e)
{
string ett = textBox1.Text;
if (ett == "")
{
MessageBox.Show("Du måste fylla i UID, vilket du finner i användarlistan.");
return;
}
try
{
if (connect.State == ConnectionState.Open)
{
MySqlCommand cmd = new MySqlCommand();
cmd.Connection = connect;
cmd.CommandText = "DELETE FROM Users WHERE uid = #uid";
cmd.Parameters.AddWithValue("#uid", textBox1.Text);
MySqlDataReader accessed = cmd.ExecuteReader();
MessageBox.Show("Användaren borttagen.");
}
else
{
MessageBox.Show("Något gick tyvärr fel, kontakta systemadministratören.");
}
}
catch (Exception ex)
{
{ MessageBox.Show(ex.Message); }
}
}
The problem may be related to this:
{
MySqlCommand cmd = new MySqlCommand();
cmd.Connection = connect;
cmd.CommandText = "DELETE FROM Users WHERE uid = #uid";
cmd.Parameters.AddWithValue("#uid", textBox1.Text);
MySqlDataReader accessed = cmd.ExecuteReader();
MessageBox.Show("Användaren borttagen.");
}
try
{
MySqlCommand cmd = new MySqlCommand();
cmd.Connection = connect;
cmd.CommandType = CommandType.Text
cmd.CommandText = "DELETE FROM Users WHERE uid = #uid";
cmd.Parameters.AddWithValue("#uid", textBox1.Text);
cmd.ExecuteNonQuery
MessageBox.Show("Användaren borttagen.");
}
Now you've shown us your whole code in the comments, the problem is obvious.
You have written a method to initialise, set up and open your database connection; and this other method which runs on a button click, which uses it.
However, nowhere in your code do you call the method which initialises your database connection, therefore it is not set up when you try to use it - obvious really.
I can see you think you are checking to see if the connection is working by checking its State property, but calling any sort of method or property accessor on an uninitialised reference type won't work, you'll get the NullReferenceException you've been getting.
To fix, call the connection set up method from your button press, before trying to use the connection:
private void button1_Click(object sender, EventArgs e)
{
string ett = textBox1.Text;
if (ett == "")
{
MessageBox.Show("Du måste fylla i UID, vilket du finner i användarlistan.");
return;
}
try
{
db_connection(); //added this line
if (connect.State == ConnectionState.Open)
{
MySqlCommand cmd = new MySqlCommand();
cmd.Connection = connect;
cmd.CommandText = "DELETE FROM Users WHERE uid = #uid";
cmd.Parameters.AddWithValue("#uid", textBox1.Text);
MySqlDataReader accessed = cmd.ExecuteReader();
MessageBox.Show("Användaren borttagen.");
}
else
{
MessageBox.Show("Något gick tyvärr fel, kontakta systemadministratören.");
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
You have not defined the variable, "connect".