Develop Reference

How to add textbox data to a database?

I am making a school project and i need to put text input (name and gender) into a database. This database (the names and genders) then have to be shown in a listbox. The code i have at the moment is put below, how can i make it work? Thanks in advance!
private void Form1_Load(object sender, EventArgs e)
{
using (connection = new SqlConnection(connectionString))
using (SqlDataAdapter adapter = new SqlDataAdapter("SELECT * FROM
Persoon", connection))
{
connection.Open();
DataTable PersoonTable = new DataTable();
adapter.Fill(PersoonTable);
lb_gebruikers.DisplayMember = "Naam";
lb_gebruikers.ValueMember = "Id";
lb_gebruikers.DataSource = PersoonTable;
}
}
private void button1_Click(object sender, EventArgs e)
{
string naam = tb_naam.Text;
string geslacht = tb_geslacht.Text;
Persoon nieuwpersoon = new Persoon(naam, geslacht);
personen.Add(nieuwpersoon);
foreach (var Persoon in personen)
{
lb_gebruikers.Items.Add("Naam: " + nieuwpersoon.Naam +
"Geslacht: " + nieuwpersoon.Geslacht);
}
}

As i understand you just have to add a insert between button1.click and addToList process.
private void btnSave_Click(object sender, EventArgs e)
{
try
{
SqlConnection con = new SqlConnection("Server =.;Database=People; Integrated Security = true");
con.Open();
SqlCommand cmd = new SqlCommand(); // you can define commandText and connection in SqlCommand(defineArea);
cmd.Connection = con; // like; cmd = newSqlCommand("Insert into...",con);
string name = txtName.Text;
string gender = txtGender.Text;
cmd.CommandText = "Insert into Person(Name,Gender)values('" + name + "','" + gender + "')";
cmd.ExecuteNonQuery();
cmd.Dispose();
con.Close();
lstBxPerson.Items.Add(name + " - " + gender);
MessageBox.Show("Save Success!");
}
catch (Exception ex)
{
MessageBox.Show("Exception : "+ex);
}
}
Database Name : People
Table Name : Person
All Parts Image :

How can I insert and save data into database using Visual Studio and C#?

public string ss = "Data Source=D\\SQLEXPRESS;Initial Catalog=gym;Integrated Security=True";
private void comboBox2_SelectedIndexChanged(object sender, EventArgs e)
{
string q2 = "insert into gym.dbo.customer (name, weight, height, add_class, gender, fees) values ('" + this.textBox1.Text + "','" + this.textBox2.Text + "','" + this.textBox3.Text + "','" + this.comboBox1.Text + "','" + this.comboBox2.Text + "','" + this.comboBox3.Text + " ') ;";
SqlConnection con = new SqlConnection(ss);
SqlCommand cmd = new SqlCommand(q2, con);
SqlDataReader read;
try
{
con.Open();
read = cmd.ExecuteReader();
MessageBox.Show("Welcome to our gym");
while (read.Read()) { };
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
How can I insert and save data into the database using Visual Studio and C#?
This code throws an error. Anyone please give the suggestion to me to solve the error.
image description

At first make sure your the data type of different column of customer table.
Then make sure what type of data you have to save for combobox.
you have to get the selected value from your Combobox. combobox1,combobox2,combobox3 retuns only the class name
System.Windows.Forms.ComboBox
Besides others, it is recommended to use parameter .. like this:
You can follow this example
private void button1_Click(object sender, EventArgs e)
{
using(SqlConnection con = new SqlConnection(#"Data Source=(LocalDB)\v11.0;AttachDbFilename=c:\users\abdul samad\documents\visual studio 2013\Projects\newpro\newpro\Database1.mdf;Integrated Security=True"))
{
try
{
using (var cmd = new SqlCommand("INSERT INTO registor (Name, FullName, Password, Email, Gander) VALUES (#Name,#Fullname,#Password,#Email, #Gander)"))
{
cmd.Connection = con;
cmd.Parameters.Add("#Name", txtfname.Text);
cmd.Parameters.Add("#Fullname", txtfname.Text);
cmd.Parameters.Add("#Password", txtpass.Text);
cmd.Parameters.Add("#Email", txtemail.Text);
cmd.Parameters.Add("#Gander", comboBox1.GetItemText(comboBox1.SelectedItem));
con.Open()
if(cmd.ExecuteNonQuery() > 0)
{
MessageBox.Show("Record inserted");
}
else
{
MessageBox.Show("Record failed");
}
}
}
catch (Exception e)
{
MessageBox.Show("Error during insert: " + e.Message);
}
}
}

The comments are getting a bit busy, so this is the sort of thing you need to do (including parameterising the query):
Specifically, you don't need a reader for an insert statement as it doesn't return a result set.
private void comboBox2_SelectedIndexChanged(object sender, EventArgs e)
{
var sql = "insert into dbo.customer ...";
using (var con = new SqlConnection(ss))
{
var cmd = new SqlCommand(sql , con);
con.Open();
cmd.ExecuteScalar();
MessageBox.Show("Welcome to our gym");
}
}

Hi check that customer table is available in gym Database.
else try this link

private void comboBox2_SelectedIndexChanged(object sender, EventArgs e)
{
SqlCommand cmd = new SqlCommand("insert into customer (name,weight,height,add_class,gender,fees) values(#name,#weight,#height,#add_class,#gender,#fees)", con);
cmd.Parameters.AddWithValue("name", this.textBox1.Text);
if (con.State == ConnectionState.Closed)
con.Open();
cmd.ExecuteNonQuery();
con.Close();
}

I found that your connection string declaration is wrong
public string ss = "Data Source=D\\SQLEXPRESS;Initial Catalog=gym;Integrated Security=True";
need to update like below
public string ss = "Data Source=abc\\SQLEXPRESS;Initial Catalog=gym; user id=sa; Password=123456";
Data source will be not be D, It should be Server name.
enter image description here

How to show the selected value from the drop down list and show it in gridview

I want it to show the selected value from the drop down list and show it on gridview. It is supposed to query from the database using Where to indicate the selected value to show. For example, I select james from the drop down list. It supposes to go to the database and query james row. After that the grid view is supposed to show only one value which james. But now I am having a problem where the grid view show every data that is available in the database.
public partial class Search_Engine : System.Web.UI.Page
{
#region Database
static string HostName = "localhost";
static string DatabaseName = "finalproject";
static string TableName = "truckinfo";
//static string TableBucket = "bucketbrigade";
static string UserName = "root";
static string Password = "";
//--- Used for access to database infomation-----
string ConnStr = "Data Source=" + HostName + ";" +
"Database=" + DatabaseName + ";" +
"User ID=" + UserName + ";" +
"Password=" + Password;
string Qry = "";
MySqlConnection Con;
MySqlCommand Cmd;
MySqlDataReader Rdr;
#endregion
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
BindData();
using (Con = new MySqlConnection(ConnStr))
{
Con.Open();
using (Cmd = new MySqlCommand("SELECT * FROM truckinfo", Con))
{
using (Rdr = Cmd.ExecuteReader())
{
if (Rdr.HasRows)
{
DropDownList1.DataSource = Rdr;
DropDownList1.DataValueField = "truckplateno";
DropDownList1.DataTextField = "truckplateno";
DropDownList1.DataBind();
}
}
}
}
}
}
private void BindData()
{
DataTable dt = new DataTable();
try
{
MySqlConnection Con = new MySqlConnection(ConnStr);
Con.Open();
MySqlDataAdapter da = new MySqlDataAdapter("SELECT * FROM " +
DatabaseName + "." + TableName , Con);
da.Fill(dt);
if (dt.Rows.Count > 0)
{
GridView1.DataSource = dt;
GridView1.DataBind();
}
Con.Close();
}
catch (Exception ex)
{
Response.Write(ex.ToString());
}
}
protected void TextBox1_TextChanged(object sender, EventArgs e)
{
}
protected void Button1_Click(object sender, EventArgs e)
{
}
protected void GridView1_SelectedIndexChanged(object sender, EventArgs e)
{
}
protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{
Con = new MySqlConnection(ConnStr);
Con.Open();
try
{
String getquery;
// String a;
getquery = DropDownList1.Text;
TextBox1.Text = getquery;
// a = TextBox2.Text;
// TextBox1.Text = a;
Qry = #"SELECT * FROM finalproject.truckinfo WHERE truckplateno=" + "'" + getquery + "'" + ";";
Cmd = new MySqlCommand(Qry, Con);
Cmd.ExecuteNonQuery();
Con.Close();
BindData();
}
catch (Exception ex)
{
Response.Write(ex.ToString());
}
}
}

You need to get the selected value using SelectedValue of dropdownlist and then query database using this value.
getquery = DropDownList1.SelectedValue;
Also you are using BindData method which will always select all data from database you need to seprate this method so only selected data is bind to gridview.
protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{
String getquery;
getquery = DropDownList1.Text;
MySqlConnection Con = new MySqlConnection(ConnStr);
Con.Open();
MySqlDataAdapter da = new MySqlDataAdapter("SELECT * FROM finalproject.truckinfo WHERE truckplateno='" + getquery + "'", Con);
da.Fill(dt);
if (dt.Rows.Count > 0)
{
GridView1.DataSource = dt;
GridView1.DataBind();
}
Con.Close();
}
You are calling ExecuteNonQuey function which is used to Insert or Update data in database so it will not return any data.
Also when using SqlDataAdapter you don't need to explicitly call
Open and Close function for opening and closing connection.

Change your DropDownlist_SelectedIndexChanged function to the following:
protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{
Con = new MySqlConnection(ConnStr);
DataTable dt = new DataTable();
try
{
Con.Open();
string getquery = DropDownList1.SelectedValue;
TextBox1.Text = getquery;
// a = TextBox2.Text;
// TextBox1.Text = a;
Qry = #"SELECT * FROM finalproject.truckinfo WHERE truckplateno=" + "'" + getquery + "'" + ";";
MySqlCommand ddlCMD = new MySqlCommand(Qry, Con);
MySqlDataAdapter msda = new MySqlDataAdapter(ddlCMD);
msda.Fill(dt);
GridView1.DataSource = dt;
GridView1.DataBind();
}
catch (Exception ex)
{
Response.Write(ex.ToString());
}
finally{
Con.Close();
}
}

Retrieve Database values and show them on form using SQLDataReader

I am trying to retrieve data from a Database and show them on a form; but my code isn't working... I've got no errors, and logically it seems to work (to me) so I cannot figure out where I have gone wrong. That's where I need your help!
private void tableListBox_SelectedIndexChanged(object sender, EventArgs e)
{
string constring = #"Data Source=(LocalDB)\v11.0;AttachDbFilename=|DataDirectory|\IncomerDefault.mdf;Integrated Security=True;Connect Timeout=30";
string Query = "SELECT * FROM [Table] WHERE Default_Name = '" + tableListBox.SelectedValue + "'";
SqlConnection con = new SqlConnection(constring);
SqlCommand cmd = new SqlCommand(Query, con);
SqlDataReader Reader;
try
{
con.Open();
Reader = cmd.ExecuteReader();
while (Reader.Read())
{
textBox1.Text = Reader.GetValue(2).ToString();
comboBox1.Text = Reader.GetValue(3).ToString();
comboBox3.Text = Reader.GetValue(4).ToString();
textBox2.Text = Reader.GetValue(6).ToString();
comboBox2.Text = Reader.GetValue(7).ToString();
comboBox4.Text = Reader.GetValue(8).ToString();
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
con.Close();
}
The 'tableListBox' is populated with all the values in column 'Default_Name'. I want it so that when the 'Default_Name' is selected from the list box it shows the values, in textboxes and comboboxes, that correspond with that row in the Database.
Any and all help would be appreciated. Thanks.

I'm going to start by changing your design a bit and suggest that perhaps you look at using a datatable and then just retrieving the rows from the datatable.
private void tableListBox_SelectedIndexChanged(object sender, EventArgs e)
{
private DataTable dataTable;
string constring = #"Data Source=(LocalDB)\v11.0;AttachDbFilename=|DataDirectory|\IncomerDefault.mdf;Integrated Security=True;Connect Timeout=30";
string Query = "SELECT * FROM [Table] WHERE Default_Name = '" + tableListBox.SelectedValue + "'";
SqlConnection con = new SqlConnection(constring);
SqlCommand cmd = new SqlCommand(Query, con);
try
{
con.Open();
SqlDataAdapter da = new SqlDataAdapter(cmd);
da.Fill(dataTable);
foreach(DataRow row in dataTable.Rows)
{
textBox1.Text = row[2].ToString();
comboBox1.Text = row[3].ToString();
comboBox3.Text = row[4].ToString();
textBox2.Text = row[6].ToString();
comboBox2.Text = row[7].ToString();
comboBox4.Text = row[8].ToString();
}
da.Dispose();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
con.Close();
}
I generally find that DataTables are more reliable than looping through the actual reader. Ofcourse this assumes that there is data being returned. Also try changing your select statement to this
string Query = "SELECT * FROM [Table]"
If that works, then the problem could be
There is no default name of the specified value or
tableListBox.SelectedValue is not returning any value, in which case, have a look at your listbox selected value

Thanks to Takarii for helping. I figured out who to make it work.
private void tableListBox_SelectedValueChanged(object sender, EventArgs e)
{
string constring = #"Data Source=(LocalDB)\v11.0;AttachDbFilename=|DataDirectory|\IncomerDefault.mdf;Integrated Security=True;Connect Timeout=30";
string Query = "SELECT * FROM [Table] WHERE ID = '" + tableListBox.SelectedIndex.ToString() + "'";
SqlConnection con = new SqlConnection(constring);
SqlCommand cmd = new SqlCommand(Query, con);
SqlDataReader Reader;
try
{
con.Open();
Reader = cmd.ExecuteReader();
while (Reader.Read())
{
textBox1.Text = Reader.GetValue(2).ToString();
comboBox1.Text = Reader.GetValue(3).ToString();
comboBox3.Text = Reader.GetValue(4).ToString();
textBox2.Text = Reader.GetValue(6).ToString();
comboBox2.Text = Reader.GetValue(7).ToString();
comboBox4.Text = Reader.GetValue(8).ToString();
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
con.Close();
}
First I changed the void to 'SelectedValueChanged' and then I changed the 'WHERE' in the connection Query to the Row Index associated with the selected Value.
Thanks for everyone's help!

The error says "The ConnectionString property has not been initialized" in c#

this code is for the combo box where i want to select some index to show it to my textboxes.
private void comboBox2_SelectedIndexChanged(object sender, EventArgs e)
{
try
{
conn.Open();
cmd.Connection = conn;
string query = "SELECT * FROM GuestInfo WHERE Groomno= '" + comboBox2.Text + "'";
db.connectDB();
db.da.SelectCommand = new OleDbCommand(query, db.conn);
db.executeQryCommand(query, false);
maxRecord = db.ds.Tables[0].Rows.Count;
loadRecords(recordCounter);
cmd.CommandText = query;
dr = cmd.ExecuteReader();
while (dr.Read())
{
textBox1.Text = dr["Gname"].ToString();
textBox2.Text = dr["Gcontactno"].ToString();
}
conn.Close();
}
catch (Exception er)
{
MessageBox.Show("Error! " + er.Message);
}
}
//My program is completely running but not in this section. :(

Is you made an connection between your application and database source using conn object ? You might be used conn object as a connection object but before this was you initialized you Connection ?
Simpy use like
"SqlConnection conn=new SqlConnection("Connection_Source");"
here is your error.

You have to define the connection string for the connection, here i suggest you one best method for executing command.
using (OleDbConnection conn = new OleDbConnection("yourconnectionString"))
{
conn.Open();
using (OleDbCommand cmd =new OleDbCommand("your query text", conn))
{
// execute your command
}
}

If its just to select value from comboBox and display in textBox , then below code will help you...
private void comboBox2_SelectedIndexChanged(object sender, EventArgs e)
{
try
{
conn.Open();
OleDbCommand cmd = new OleDbCommand("SELECT Gname,Gcontactno FROM GuestInfo WHERE Groomno= '" + comboBox2.Text + "'", conn);
OleDbDataReader dr = cmd.ExecuteReader();
while (dr.Read())
{
textBox1.Text = dr[0].ToString();
textBox2.Text = dr[1].ToString();
}
conn.Close();
}
catch (Exception er)
{
MessageBox.Show("Error! " + er.Message);
}
}