How to retrieve data from postgres to textbox in c#.net

How to retrieve data from postgres to textbox in c#.net - c#

I want to retrieve data from postgres db into textbox in C# without using grid.
Here is the running successful code by using grid which I had tried:
connection.Open();
NpgsqlCommand cmd = new NpgsqlCommand();
cmd.Connection = connection;
cmd.CommandText = "SELECT * FROM student_folio";
cmd.CommandType = CommandType.Text;
NpgsqlDataAdapter da = new NpgsqlDataAdapter(cmd);
DataTable dt = new DataTable();
da.Fill(dt);
cmd.Dispose();
connection.Close();
GridView1.DataSource = dt;
GridView1.DataBind();
I get error when build when I want to retrieve it into textbox:
"cannot apply indexing with [] to an expression of type 'NpgsqlDataAdapter'"
Here is my block of code:
connection.Open();
NpgsqlCommand cmd = new NpgsqlCommand();
cmd.Connection = connection;
cmd.CommandText = ("SELECT f_name FROM student_folio WHERE id = 1");
cmd.CommandType = CommandType.Text;
NpgsqlDataAdapter da = new NpgsqlDataAdapter(cmd);
txtFname.Text = da["f_name"].ToString();
cmd.ExecuteNonQuery();
cmd.Dispose();
connection.Close();

A DataAdapter is not an array of rows you can loop into.
Look at your first code block : you must fill a DataTable from your adapter and then read through the Rows property of this DataTable.
NpgsqlDataAdapter da = new NpgsqlDataAdapter(cmd);
DataTable dt = new DataTable();
da.Fill(dt);
if (dt.Rows.Count > 0)
{
txtFname.Text = dt.Rows[0]["f_name"].ToString();
}
You could also do this :
foreach (System.Data.DataRow row in dt.Rows)
{
txtFname.Text = row["f_name"].ToString();
}
And please, remove the cmd.ExecuteNonQuery(); line, it is useless here

try this . .
connection.Open();
NpgsqlCommand cmd = new NpgsqlCommand();
NpgsqlDataReader dr=null;
cmd.Connection = connection;
cmd.CommandText = ("SELECT f_name FROM student_folio WHERE id = 1");
cmd.CommandType = CommandType.Text;
dr=cmd.ExecuteReader();
while(dr.HasRows)
{
while(dr.Read())
{
txtFname.Text = da["f_name"].ToString();
}
}
connection.Close();

Related

Newly added data from Database not showing on ComboBox

Please help when i insert a new data to the database it is not showing in the comboBox unless i restart the program. Is something missing from this ?
CmbSupp.Items.Clear();
con.Open();
Refresh();
SqlCommand cmd = con.CreateCommand();
cmd.CommandType = CommandType.Text;
cmd.CommandText = "select SupplierName from SuppTbl";
cmd.ExecuteNonQuery();
DataTable dt = new DataTable();
SqlDataAdapter dp = new SqlDataAdapter(cmd);
dp.Fill(dt);
foreach (DataRow dr in dt.Rows)
{
CmbSupp.Items.Add(dr["SupplierName"].ToString());
}
con.Close();
Thankyou in advance!

Change
CmbSupp.Items.Clear()
To CmbSupp.Items = null;
this is a small Bug,You have to set Null Value and Reset Data;
Try It;

You could do this:
DataTable dt = new DataTable();
private void RefreshData()
{
dt.Clear();
con.Open();
Refresh();
SqlCommand cmd = con.CreateCommand();
cmd.CommandType = CommandType.Text;
cmd.CommandText = "select SupplierName from SuppTbl";
cmd.ExecuteNonQuery();
SqlDataAdapter dp = new SqlDataAdapter(cmd);
dp.Fill(dt);
con.Close();
cmd.Dispose();
}
private void BindToComboBox()
{
CmbSupp.DataSource = dt;
CmbSupp.ValueMember = "SupplierName";
CmbSupp.DisplayMember = "SupplierName";
}
Ideally, you include the table's ID and put it in ValueMember property. You call the Bind ToComboBox once and just call RefreshData() when there's changes in the database. It should automatically update the contents of the combobox.

Remoting client server asp.net

I have this code in the server side.
public DataTable DIS(int IID)
{
SqlConnection con = new
SqlConnection(Properties.Settings.Default.ADP_C1ConnectionString);
con.Open();
SqlCommand cmd = con.CreateCommand();
cmd.CommandType = CommandType.Text;
cmd.CommandText = "Select * from Paper";
cmd.ExecuteNonQuery();
DataTable DT = new DataTable();
SqlDataAdapter DA = new SqlDataAdapter(cmd);
DA.Fill(DT);
con.Close();
return DT;
}
I want to make the grid view in the client side take its source from that function like this:
public void dis_data()
{
DataTable DT = mgr.DIS(JouranlIID);
sda.Fill(DT);
dataGridView1.DataSource = DT;
}
How to do that?

How do I get last input to column (ID)

I have this code that is suppose to get me the last registered MemberId from column but I cant get it to work, what have I got wrong?
if (con.State == ConnectionState.Open)
{
con.Close();
}
con.Open();
SqlCommand cmd = con.CreateCommand();
cmd.CommandType = CommandType.Text;
cmd.CommandText = "SELECT top 1 * FROM Medleminfo ORDER BY MemberId desc";
cmd.ExecuteNonQuery();
DataTable dt = new DataTable();
SqlDataAdapter da = new SqlDataAdapter(cmd);
da.Fill(dt);
foreach (DataRow dr in dt.Rows)
{
last_id = Convert.ToInt32(dr["MemberId"].ToString());
}
return last_id;
Output last_id is supposed to be used in this method:
public DataTable display_tiger_info(int member_id)
{
if (con.State == ConnectionState.Open)
{
con.Close();
}
con.Open();
SqlCommand cmd = con.CreateCommand();
cmd.CommandType = CommandType.Text;
cmd.CommandText = #"SELECT Medleminfo.MemberId, Medleminfo.Förnamn, Medleminfo.Efternamn,
Medleminfo.Adress, Medleminfo.Telefon, Tigerinfo.Tigernamn,Tigerinfo.Födelsedatum
FROM Medleminfo, Tigerinfo WHERE Medleminfo.MemberId = Tigerinfo.OwnerID ";
cmd.ExecuteNonQuery();
DataTable dt = new DataTable();
SqlDataAdapter da = new SqlDataAdapter(cmd);
da.Fill(dt);
return dt;
}

Why not just use the 'Max' function? This is assuming that your looking for the largest number in the sequence. The way your question is worded though would suggest that you should have a date column to search by instead. Also if you want just one result then try execute scalar instead of putting it into a data table and going through all that extra work.
int id = 0;
using (SqlConnection connection = new SqlConnection(connectionString))
{
connection.Open();
using(var command = new SqlCommand("Select Max(MemberId) from Medleminfo", connection))
{
id = (int)command.ExecuteScalar();
}
}

I think your issues is probably cmd.ExecuteNonQuery() according to the msdn SqlCommand.ExecuteNonQuery Method Executes a Transact-SQL statement against the connection and returns the number of rows affected.
You will probably be wanting to use ExecuteReader in something like the following
if (con.State == ConnectionState.Open)
{
con.Close();
}
con.Open();
SqlCommand cmd = con.CreateCommand();
cmd.CommandType = CommandType.Text;
//All you want is the member Id why get all the columns
cmd.CommandText = "SELECT top 1 MemberId FROM Medleminfo ORDER BY MemberId desc";
SqlDataReader reader = cmd.ExecuteReader();
while (reader.Read())
{
last_id = Convert.ToInt32( reader[0]));
}
return last_id;
UPDATE: This code might solve your problem but I did not identify the issue correctly cmd.ExecuteNonQuery() should be removed it is not doing anything. adapter.Fill() should be executing the command and I do not know why you are not getting the expected response.

Fetch data from database based on checkbox on button click

I have table consisting columns(....,....,....,BLOCK) in my database.
The BLOCK column has bit datatype(True,False).
When BLOCK column has False, the data should be fetched from the database.
When BLOCK column has True, the data should not be fetched resulting in throwing an error.
When I give the name of a particular person in textbox and click button, the above operation must be performed
my button click c# coding is...
protected void ImageButton5_Click(object sender, ImageClickEventArgs e)
{
string selectsql = "SELECT * FROM UserDetailsTwo";
using (SqlConnection con = new SqlConnection(#"Data Source=ENTERKEY001;Initial Catalog=ContactManagement;Integrated Security=True"))//DataBase Connection
{
SqlCommand selectCommand = new SqlCommand(selectsql, con);
con.Open();
SqlDataReader SelectReader = selectCommand.ExecuteReader();
while (SelectReader.Read())
{
Boolean BLOCK = Convert.ToBoolean(SelectReader["BLOCK"]);
if (BLOCK == false)
{
//con.Open();
SqlCommand cmd = con.CreateCommand();
cmd.CommandType = CommandType.StoredProcedure;
cmd.CommandText = "SearchUser";
cmd.Parameters.AddWithValue("#NAME", TextBox4.Text.Trim());
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataTable dt = new DataTable();
da.Fill(dt);
GridView1.DataSource = dt;
GridView1.DataBind();
con.Close();
}
else
{
Response.Write("Error");
}
}
SelectReader.Close();
}
}

You are trying to use an SQLDataReader like a DataAdapter.
SelectReader = selectCommand.ExecuteReader();
while (SelectReader.Read())
{
Int64 BLOCK = Convert.ToInt64(SelectReader["BLOCK"]);
if (BLOCK == false)
{
con.Open();
SqlCommand cmd = con.CreateCommand();
cmd.CommandType = CommandType.StoredProcedure;
cmd.CommandText = "SearchUser";
cmd.Parameters.AddWithValue("#NAME", TextBox4.Text.Trim());
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataTable dt = new DataTable();
da.Fill(dt);
GridView1.DataBind();
con.Close();
}
else
{
Response.Write("Error");
}
}
https://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqldatareader%28v=vs.110%29.aspx

How to get data from SQL database to store in combo box - C#

How can i get the value of company_name from Comp table and store it on a comboBox?
here is my initial code on getting the values from Database and store it on a combobox:
string Sql = "select company_name from JO.dbo.Comp";
SqlConnection conn = new SqlConnection(connString);
SqlCommand cmd = new SqlCommand(Sql, conn);
cmd.CommandType = CommandType.StoredProcedure;
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataSet ds = new DataSet();
da.Fill(ds);
for (int i = 0; i < ds.Tables[0].Rows.Count; i++)
comboBox1.Items.Add(ds.Tables[0].Rows[i][0].ToString());
it point out to da.fill(ds) and says "Could not locate entry in sysdatabases for database 'select company_name from JO'. No entry found with that name. Make sure that the name is entered correctly."
hope for your reply thanks!

Use datareader it is much simpler \
string Sql = "select company_name from JO.dbo.Comp";
SqlConnection conn = new SqlConnection(connString);
conn.Open();
SqlCommand cmd = new SqlCommand(Sql, conn);
SqlDataReader DR = cmd.ExecuteReader();
while (DR.Read())
{
combobox1.Items.Add(DR[0]);
}

If you set up your connection string to be something of this sort:
string SqlConnectionString = "Data Source=[SERVER];Initial Catalog=[DATABASE];"
Then using that set up, you can set your string 'Sql' as:
string Sql = "select company_name from dbo.Comp";
This could be a possible set up you could use to read out the values.
using (SqlConnection saConn = new SqlConnection(this.ConnectionString))
{
saConn.Open();
string query = "select DBName from dbo.Company";
SqlCommand cmd = new SqlCommand(query, saConn);
using (SqlDataReader saReader = cmd.ExecuteReader())
{
while (saReader.Read())
{
string name = saReader.GetString(0);
combobox1.Add(name);
}
}
saConn.Close();
}

I would like to introduce you a very simple way to SQL data into a combobox as:
first you have a create a SQL table,
in C# platform drop a combobox and go to its property,
in the property menu click on "DataSource"
specify the database and table to load into combobox,
Note, the combobox name and table's row should be the same.

{
SqlConnection con =new SqlConnection("Data Source=Server_Name;Initial Catalog=Database_Name;integrated security=true");
SqlCommand cmd;
SqlDataReader dr;
private void CashMemoForm_Load(object sender, EventArgs e)
{
con.Open();
cmd = new SqlCommand("Select Column_Name From Table_Name", con);
dr = cmd.ExecuteReader();
while (dr.Read())
{
comboBox1.Items.Add(dr[0]).ToString();
}
}
}

Have you ever tried Entity Framework for database access and dto creation?

Change your line to cmd.CommandType = CommandType.Text; instead of cmd.CommandType = CommandType.StoredProcedure;

Try this
string Sql = "select Company_ID,company_name from JO.dbo.Comp";
SqlConnection conn = new SqlConnection(connString);
SqlCommand cmd = new SqlCommand(Sql, conn);
cmd.CommandType = CommandType.Text;
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataSet ds = new DataSet();
da.Fill(ds);
for (int i = 0; i < ds.Tables[0].Rows.Count; i++)
{
comboBox1.DataSource = ds.Tables[0];
comboBox1.DataTextField = "company_name";
comboBox1.DataValueField = "Company_ID";
comboBox1.DataBind();
comboBox1.Items.Insert(0, new ListItem("--Select--", "0"));
}

There is no use of for loop. you just need to check that whether the dataset contains rows or not.
string Sql = "select Company_ID,company_name from JO.dbo.Comp";
SqlConnection conn = new SqlConnection(connString);
SqlCommand cmd = new SqlCommand(Sql, conn);
cmd.CommandType = CommandType.Text;
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataSet ds = new DataSet();
da.Fill(ds);
if (ds.Tables[0].Rows.Count > 0)
{
comboBox1.DataSource = ds.Tables[0];
comboBox1.DataTextField = "company_name";
comboBox1.DataValueField = "Company_ID";
comboBox1.DataBind();
comboBox1.Items.Insert(0, new ListItem("Select", "0"));
}

string Sql = "select company_name from JO.dbo.Comp";
SqlConnection conn = new SqlConnection(connString);
SqlCommand cmd = new SqlCommand(Sql, conn);
cmd.CommandType = CommandType.StoredProcedure;
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataSet ds = new DataSet();
da.Fill(ds);
for (int i = 0; i < ds.Tables[0].Rows.Count; i++)
comboBox1.Items.Add(ds.Tables[0].Rows[i][0].ToString());

public System.Data.DataTable EmployeeViewAll()
{
DataTable dtbl = new DataTable();
try
{
// Here it shuld be your database Connection String
string connectionString = "Server = .; database = HKS; Integrated Security = true";
using (SqlConnection sqlCon = new System.Data.SqlClient.SqlConnection(connectionString))
{
SqlDataAdapter SqlDa = new SqlDataAdapter("employeeViewAll", sqlCon);
SqlDa.SelectCommand.CommandType = CommandType.StoredProcedure;
SqlDa.Fill(dtbl);
}
return dtbl;
}
catch (Exception)
{
throw;
}
}
public void ComboFill()
{
DataTable dt = new DataTable();
eSP SP = new eSP();
d = SP.EmployeeViewAll();
comboBox1.DataSource = dt;
comboBox1.DisplayMember = "department";
comboBox1.ValueMember = "empName";
}

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C# (C-Sharp) is a programming language developed by Microsoft that runs on the .NET Framework.

How to retrieve data from postgres to textbox in c#.net - c#

Related

Newly added data from Database not showing on ComboBox

Remoting client server asp.net

How do I get last input to column (ID)

Fetch data from database based on checkbox on button click

How to get data from SQL database to store in combo box - C#

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