Comments by arave0521 (Top 50 by date)

when I do breakpoint, I found it it the problem because of command.ExecuteNonQuery();inside for looping. It said object reference is not set to instance.
this part of code

conn.Open();
for (i = 0; i < Main.dbMetName.Rows.Count; i++)
{
command.CommandText = "INSERT INTO " + database +
".Metabolites " +
"(MetaboliteID, Metabolite_Name)" +
"VALUES " +
"('" + Main.dbMetName.Rows[i].Cells[0].Value.ToString()
+ "' , '" +
Main.dbMetName.Rows[i].Cells[1].Value.ToString() + "')";
command.ExecuteNonQuery();
}
conn.Close();

where all of declaration of object and variable are made inside constructor. and global part

it works. just because I did not set the DataGridView.AllowUserToAddRows = false in the function. sorry for not mentioning at first. thank you so much btw.

There is a problem with the code. The code quite similar with the one I tried before and it produce the same error. The error is uncommitted new row cannot be deleted

how to remove 1 whole row if let say there are two column and two column has no value. some sort like this code
DataGridView1.Rows.Remove(_row);

yes. the first form actually allowed user to add how many row he want. but when it comes to second form which showing the datagridview which only allowed user to edit and not allowed him to add at all.

problem solved
thanks !!! :)

User can insert the amount of car more than the availability of car.
However,for second input user cannot enter the case because the amount car is less or equal than 0.

yes. I tried to put dbSumMetabolite.DataSource = null;
It is not working.

not working. still produce duplication

Hi, It has a bit problem. how to make sure the data is not duplicate when we update? I try put dbSumMetabolite.ResetBindings(); it does not work

It works. thanks.

There is an error saying that rows cannot be programamtically added to datagridview rows collection when control is data-bound

yes. I have predefine the column of the datagridview. 1st column DataPropertyName is "Metabolite ID" and Header Text "Metabolite ID". 2nd Column DataPropertyName is "Metabolite Name" and Header Text is "Metabolite Name"

the data is not placed on respective column. what code should i put to make it inserted in respective column

I still don't get it. Okay right now I have two predefined column in design. And I want to insert the sql statement based on the respective column. Can you show any tutorial on this. Thanks

Hai. may I know more details? I'm quite beginner in mysql and datagridview

The code already works! only the matter of arrangement at command.commandText. Thanks for the help. I appreciate it!

Here is the project file that I am stuck
https://www.dropbox.com/s/c8z58opqorplom6/DynamicSimulator_v2.zip

The database has being populated. I had checked it in Mysql workbench. When I run the modified code, it says that error in SQL syntax near '.Metabolites WHERE MetaboliteID IN ('met1', 'met2');

the code still have proble with sql command. I pretty sure the query was right.

If I'm using ExecuteReader, can I insert and edit data during runtime? Can you show it based on my code. I still don't get it. Thanks

hai, i don't get it where should i put the break points. i thought if we put
<pre> break; </pre>

it resulting error in if else statements

yes, it goes to the condition but the datagridview only shows plain grey panel

I had update the problem of code. thanks for reminding

Dear Sergey Alexandrovich,
I had update the code. Thanks for the reminding.

Hai, this is my code. I wrote it by referring from the tutorial and make some modification.

hai,
I tried insert
dbMetName.DataBind();

it says there is no extension of it in datagridview.

Ohh, my mistake. Suppose the both of the
command.ExecuteNonQuery();
conn.Close();
are in comments mode.
But still the database is not selected.
i try modified using add parameter value the error said that fatal error occur. here is the code

try
{
MySqlCommand command = conn.CreateCommand();
conn.Open();
command.CommandText = "DROP DATABASE IF EXISTS " + database;
command.ExecuteNonQuery();
command.CommandText = "CREATE DATABASE " + database;
command.ExecuteNonQuery();
conn.Close();
conn.ConnectionString = connStr;
MySqlCommand comm = conn.CreateCommand();
conn.Open();
comm.CommandText = "CREATE TABLE @schema.Metabolites(MetaboliteID VARCHAR(10) NOT NULL, Metabolite_Name VARCHAR(45) NULL, ReactionTime INT NULL, PRIMARY KEY (MetaboliteID)";
comm.Parameters.AddWithValue("@schema", database);
comm.ExecuteNonQuery();
this.Hide();
form2.Show();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
conn.Close();

private void btnNew_Click(object sender, EventArgs e)
{
SchemaName schemaForm = new SchemaName();
frmMetCon form2 = new frmMetCon();

if (schemaForm.ShowDialog() == System.Windows.Forms.DialogResult.OK)
{

string connStr = "datasource=localhost;port=3306;username=root;password=root;";
string database = schemaForm.getData();
MySqlConnection conn = new MySqlConnection(connStr);
try
{
MySqlCommand command = conn.CreateCommand();
conn.Open();
command.CommandText = "DROP DATABASE IF EXISTS " + database;
command.ExecuteNonQuery();
command.CommandText = "CREATE DATABASE " + database;
command.ExecuteNonQuery();
conn.Close();
command.ExecuteNonQuery();
conn.Close();
conn.ConnectionString = connStr;
MySqlCommand comm = conn.CreateCommand();
conn.Open();
comm.CommandText = "CREATE TABLE Metabolites(MetaboliteID VARCHAR(10) NOT NULL, Metabolite_Name VARCHAR(45) NULL, ReactionTime INT NULL, PRIMARY KEY (MetaboliteID)";
comm.ExecuteNonQuery();
this.Hide();
form2.Show();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
conn.Close();

}
}
}

Here is the code I try modified based on you given example. the problem i'm facing now is the conn is not open. i insert open connection but still the same error appear. Any advise?

there is an error on con.connsectionstring=Connectionstring;// this will contain the same server information but database information is the new one,

I don't get it. do you mind showing example?

I tried but still got error. The error said that no database selected. if I create

try
{
MySqlCommand command = conn.CreateCommand();
conn.Open();
command.CommandText = "DROP DATABASE IF EXISTS " + schemaForm.getData();
command.ExecuteNonQuery();
command.CommandText = "CREATE DATABASE " + schemaForm.getData();
command.ExecuteNonQuery();
command.Parameters.AddWithValue("@schema",database);
command.CommandText = "CREATE TABLE @schema.Metabolites(MetaboliteID VARCHAR(10) NOT NULL, Metabolite_Name VARCHAR(45) NULL, ReactionTime INT NULL, PRIMARY KEY (MetaboliteID)";
command.ExecuteNonQuery();
this.Hide();
form2.Show();
}

there is still an error

There is nothing wrong with the connection. It works fine. The proble I'm facing is the command of creating table based on user defined the database name
command.CommandText = "CREATE TABLE" +schemaForm.getData()+ ".Metabolites(MetaboliteID VARCHAR(10) NOT NULL, Metabolite_Name VARCHAR(45) NULL, ReactionTime INT NULL, PRIMARY KEY (MetaboliteID)";

winforms

thanks for the tips once again =)

Schema is the right word. The only problem is I'm using a ExecuteReader(). I just solved it by using ExecuteNonQuery()

Thanks for the help. I'm using ExecuteNonQuery(). And it is working. Thanks. May I know the differences of ExecuteNonQuery() and ExecuteReader in your perspective point of view. I thought both are quite the same

May I know how to set it as property. Quite new in c#.net

In form2.
FORM2(schemaName)

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace DynamicSimulator_v2
{
public partial class SchemaName : Form
{
private string data;

public SchemaName()
{
InitializeComponent();
}

private void btnCancel_Click(object sender, EventArgs e)
{
this.Hide();
}

private void btnOK_Click(object sender, EventArgs e)
{
data=txtDB.Text;
this.Hide();
}

public string getData()
{
return data;
}

}
}


FORM1(frmMain)


namespace DynamicSimulator_v2
{
public partial class frmMain : Form
{
public frmMain()
{
InitializeComponent();
}

private void btnExit_Click(object sender, EventArgs e)
{
Application.Exit();
}

private void btnNew_Click(object sender, EventArgs e)
{
string data = frm.getData(); //get data from Form2
SchemaName schemaForm = new SchemaName();
if (schemaForm.ShowDialog() == System.Windows.Forms.DialogResult.OK)
{
MessageBox.Show(data);
string connStr = "datasource=localhost;port=3306;username=root;password=root;";
MySqlConnection conn = new MySqlConnection(connStr);
try
{
conn.Open();
MySqlCommand cmdDatabase = new MySqlCommand("CREATE SCHEMA @schema; ", conn);
cmdDatabase.Parameters.AddWithValue("@schema",data);
MySqlDataReader myReader;
myReader = cmdDatabase.ExecuteReader();
myReader.Close();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
conn.Close();

}
}
}
}

FORM2(schemaName)

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace DynamicSimulator_v2
{
public partial class SchemaName : Form
{
private string data;

public SchemaName()
{
InitializeComponent();
}

private void btnCancel_Click(object sender, EventArgs e)
{
this.Hide();
}

private void btnOK_Click(object sender, EventArgs e)
{
data=txtDB.Text;
this.Hide();
}

public string getData()
{
return data;
}

}
}


FORM1(frmMain)


namespace DynamicSimulator_v2
{
public partial class frmMain : Form
{
public frmMain()
{
InitializeComponent();
}

private void btnExit_Click(object sender, EventArgs e)
{
Application.Exit();
}

private void btnNew_Click(object sender, EventArgs e)
{
string data = frm.getData(); //get data from Form2
SchemaName schemaForm = new SchemaName();
if (schemaForm.ShowDialog() == System.Windows.Forms.DialogResult.OK)
{
MessageBox.Show(data);
string connStr = "datasource=localhost;port=3306;username=root;password=root;";
MySqlConnection conn = new MySqlConnection(connStr);
try
{
conn.Open();
MySqlCommand cmdDatabase = new MySqlCommand("CREATE SCHEMA @schema; ", conn);
cmdDatabase.Parameters.AddWithValue("@schema",data);
MySqlDataReader myReader;
myReader = cmdDatabase.ExecuteReader();
myReader.Close();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
conn.Close();

}
}
}
}

The value of schemaForm.getData()is user define value which is I'm not stated. the code.
Here is the code of schemaForm

public partial class SchemaName : Form
{
private string data;

public SchemaName()
{
InitializeComponent();
}

private void btnCancel_Click(object sender, EventArgs e)
{
this.Hide();
}

private void btnOK_Click(object sender, EventArgs e)
{
data=txtDB.Text;
this.Hide();
}

public string getData()
{
return data;
}

}

The error given is that You have an error in your SQL syntax, check the manual that corresponds to your MYSQL server version for the right syntax to use near "user-defined-schemaName" at line 1

parent form is Form1

Thank you for your help. =)

I'm quite new in using codeDom. im not really understand about it related to my problem.thanks