This one is a mystery for me, I know the code I took it from others, in my case the datatable it returns is empty
conSTR is the connection string, set as a global string
public DataTable fillDataTable(string table)
{
string query = "SELECT * FROM dstut.dbo." +table;
SqlConnection sqlConn = new SqlConnection(conSTR);
sqlConn.Open();
SqlCommand cmd = new SqlCommand(query, sqlConn);
DataTable dt = new DataTable();
dt.Load(cmd.ExecuteReader());
sqlConn.Close();
return dt;
}
EDIT 1
The whole point is to later show this table in a datagrid view on a tabcontrol, here is the question on that
displaying multiple datatable in tabcontrol C#
Here it just show's me a blank datagridview
EDIT 2
Tried them all, when I try to display the table, the datagridview is empty, have the right amount of rows but now value
If the variable table contains invalid characters (like a space) you should add square brackets around the variable.
public DataTable fillDataTable(string table)
{
string query = "SELECT * FROM dstut.dbo.[" + table + "]";
using(SqlConnection sqlConn = new SqlConnection(conSTR))
using(SqlCommand cmd = new SqlCommand(query, sqlConn))
{
sqlConn.Open();
DataTable dt = new DataTable();
dt.Load(cmd.ExecuteReader());
return dt;
}
}
By the way, be very careful with this kind of code because is open to Sql Injection. I hope for you that the table name doesn't come from user input
Try with following:
public DataTable fillDataTable(string table)
{
string query = "SELECT * FROM dstut.dbo." +table;
SqlConnection sqlConn = new SqlConnection(conSTR);
sqlConn.Open();
SqlCommand cmd = new SqlCommand(query, sqlConn);
SqlDataAdapter da=new SqlDataAdapter(cmd);
DataTable dt = new DataTable();
da.Fill(dt);
sqlConn.Close();
return dt;
}
Hope it is helpful.
Related
Hello internet so first i am newbie at c# and i am doing project about changing data from a sql table. I passed the result of the query to the datatable and datagridview, but what i want next is i want the modified datagridview table passing to a dataset. this is how i get my table from the sql:
string query = "select Article,Barcode,\"Minimum Stock\",\"Current Stock\" from article where Fid=2 and \"Minimum Stock\" > \"Current Stock\"";
SqlConnection conn = new SqlConnection(connString);
SqlCommand cmd = new SqlCommand(query, conn);
conn.Open();
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataTable dt = new DataTable();
da.Fill(dt);
dataGridView1.DataSource = dt;
conn.Close();
da.Dispose();
Now the users will modifie the table and valid the information. How can i save it to a dataset?
I tried to bind dataset to the datagridview:
Dataset1.Tables.Add(datagridview1.datasource);
But it threw a error where it says datasource doesn't use here
Can anyone help?
I have created a table name glossary in a database named ChatBotDataBase in SQL Server. I want to read the data in a special column of the table.
To do so, I have written this code:
private void button1_Click(object sender, EventArgs e)
{
SqlConnection sc = new SqlConnection();
sc.ConnectionString = #"Data Source=shirin;Initial Catalog=ChatBotDataBase;
Integrated Security=True";
SqlDataAdapter sda = new SqlDataAdapter();
sda.SelectCommand = new SqlCommand();
sda.SelectCommand.Connection = sc;
sda.SelectCommand.CommandText = "SELECT * FROM glossary";
DataTable table = new DataTable();
MessageBox.Show(table.Rows[0].ItemArray[3].ToString());
}
But there is an error in last line.
The error is :
An unhandled exception of type 'System.IndexOutOfRangeException' occurred in System.Data.dll.
And here is a print screen of the mentioned table:
Can anyone help please?
Looks like you are confusing the Datatable called table with your database table in your sql server. In your image you show us the glossary table in your sql server, not the DataTable called table.
You get this error because you create an empty DataTable called table with DataTable table = new DataTable() but you didn't even fill your table. That's why it doesn't have any rows by default.
SqlCommand cmd = new SqlCommand("SELECT * FROM glossary");
SqlDataAdapter sda = new SqlDataAdapter(cmd);
sda.Fill(table);
Also use using statement to dispose your SqlConnection, SqlCommand and SqlDataAdapter.
using(SqlConnection sc = new SqlConnection(conString))
using(SqlCommand cmd = sc.CreateCommand())
{
cmd.CommandText = "SELECT * FROM glossary";
...
using(SqlDataAdapter sda = new SqlDataAdapter(cmd))
{
DataTable table = new DataTable();
sda.Fill(table);
if(dt.Rows.Count > 0)
MessageBox.Show(table.Rows[0].ItemArray[3].ToString());
}
}
Below code will help you
sda.SelectCommand.CommandText = "SELECT * FROM glossary";
DataTable table = new DataTable();
sda.Fill(table , "glossary");
MessageBox.Show(table.Rows[0].ItemArray[3].ToString());
You haven't executed the query or populated the table. It is empty. It has no columns and no rows. Hence the error.
Frankly, though, I strongly suggest using a typed class model, not any kind of DataTable. With tools like "dapper", this can be as simple as:
var list = conn.Query<Glossary>("SELECT * FROM glossary").ToList();
With
public class Glossary {
public int Id {get;set}
public string String1 {get;set} // horrible name!
....
public int NumberOfUse {get;set}
}
Dear kindly first fill your table with the data.
And you should use checks because if there is no data then you get a proper message.check is below..
if(dt.Rows.Count > 0)
MessageBox.Show(table.Rows[0].ItemArray[3].ToString());
else if(dt.Rows.Count > 0)
MessageBox.Show("Table is empty");
And other advice is that you should display data into DataGrid.... Displaying data from Database into a message box is not a good programming approach..
For displaying DataTable into DataGrid in C# is as simple as below.
SqlCommand cmd = new SqlCommand("select * from student",con);
SqlDataAdapter da = new SqlDataAdapter();
da.SelectCommand = cmd;
DataTable dt = new DataTable();
dt.TableName = "students";
da.Fill(dt);
dataGridView1.DataSource =dt;
using System.Data.Odbc;
OdbcConnection con = new OdbcConnection("<connectionstring>");
OdbcCommand com = new OdbcCommand("select * from TableX",con);
OdbcDataAdapter da = new OdbcDataAdapter(com);
DataSet ds = new DataSet();
da.Fill(ds,"New");
DataGrid dg = new DataGrid();
dg.DataSource = ds.Tables["New"];
you can get the connection string from:
http://www.connectionstrings.com/
How use WHERE in SqlDataAdapter in C#?
I want get name in a textbox and use that at query but it wont work .
SqlConnection sqlconnection = new SqlConnection("Server=Behnam\\Accounting;Initial Catalog=Accounting;Integrated Security=TRUE");
DataTable dt = new DataTable();
string _search_name = txt_search.Text;
SqlDataAdapter SDA = new SqlDataAdapter("SELECT dbo.tbl_user.field1,dbo.tbl_user.field2 FROM tbl_user WHERE dbo.tbl_user.name=_search_name ", sqlconnection);
SDA.Fill(dt);
dataGridView1.DataSource = dt;
Prepare the command text and use a parameter for the value of your search.
Then use that command text to initialize a new SqlCommand. Fill the parameter value with AddWithValue and pass the SqlCommand to the constructor of the SqlDataAdapter.
string cmdText = "SELECT dbo.tbl_user.field1,dbo.tbl_user.field2 " +
"FROM tbl_user WHERE dbo.tbl_user.name=#search_name"
SqlCommand cmd = new SqlCommand(cmdText, sqlconnection);
cmd.Parameters.AddWithValue("#search_name", _search_name);
SqlDataAdapter SDA = new SqlDataAdapter(cmd);
The SqlDataAdapter will store your command as the SelectCommand property and will use the passed in SqlCommand to execute the query to retrieve the records from the database.
Keep in mind that AddWithValue is a shortcut with some drawbacks. For example it pass Always a string as a nvarchar parameter with size equal to the actual lenght of the variable. This effectively reduces the performance of the Sql Server Optimizer.
This is a very enlightening article on the issue
So, you were pretty close, you just needed to define a parameter inside the query and then add that parameter. However, in the following code block I've also conveniently recommended a more appropriate approach to using the classes needed to get the data (pun intended). The using statement here ensures that the objects get disposed of properly after you are done using them (man I just can't stop with the puns!)
using (SqlConnection c = new SqlConnection(connString))
{
c.Open();
using (SqlDataAdapter sda = new SqlDataAdapter(
"SELECT dbo.tbl_user.field1, dbo.tbl_user.field2 FROM tbl_user " +
"WHERE dbo.tbl_user.name= #name", c))
{
sda.SelectCommand.Parameters.AddWithValue("#name", txt_search.Text);
DataTable dt = new DataTable();
sda.Fill(dt);
}
}
Try this.
you were using the string directly in the query which will go undetected.
SqlConnection sqlconnection = new SqlConnection("Server=Behnam\\Accounting;
Initial Catalog=Accounting;Integrated Security=TRUE");
DataTable dt = new DataTable();
SqlDataAdapter SDA = new SqlDataAdapter("SELECT dbo.tbl_user.field1,dbo.tbl_user.field2 FROM tbl_user WHERE dbo.tbl_user.name=#searchName" , sqlconnection);
SDA.SelectCommand.Parameters.AddWithValue("#searchName", txt_search.Text);
SDA.Fill(dt);
dataGridView1.DataSource = dt;
I want to select all customer information where customerid = the selected customerid stored in the combo box and show the result in datagridview I tried this code but the gridview doesnot show result.
private void button1_Click(object sender, EventArgs e)
{
SqlConnection con = new SqlConnection(constring);
int id = Convert.ToInt32(comboBox1.SelectedValue);
string cmdstring=string.Format("select *from customers where customer_id={0}",id);
SqlCommand cmd = new SqlCommand(cmdstring,con);
//cmd.Parameters.AddWithValue("#id",id);
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataSet ds = new DataSet();
//da.Fill(ds, "customers");
//dataGridView1.DataSource = ds.Tables["customers"];
con.Open();
SqlDataReader red = cmd.ExecuteReader();
con.Close();
dataGridView1.DataSource = red;
button = new DataGridViewButtonColumn();
button.HeaderText = "edit";
button.Tag = ds.Tables["customers"].Columns["customer_id"];
dataGridView1.Columns.Add(button);
}
you could always make a DataBase Class and if you need to refactor this Class to pass in Connection String or read Connection string from .Config File you can use this as a template to get started plus it's a lot cleaner
Notice that I am returning a DataTable you can use this if you like just a suggestion
public class ClassDataManagement
{
public DataTable GetData(string sqlcmdString, string connString)
{
SqlConnection con = new SqlConnection(connString);
SqlCommand cmd = new SqlCommand(sqlcmdString, cn);
SqlDataAdapter da = new SqlDataAdapter(cmd);
con.Open();
DataTable dt = new DataTable();
da.Fill(dt);
return dt;
}
}
if you want to use DataSet instead of DataTable replace where i have DataTable with
or change the method to return a DataSet like this below
public DataSet GetData(string sqlcmdString, string connString)
{
SqlConnection con = new SqlConnection(connString);
SqlCommand cmd = new SqlCommand(sqlcmdString, cn);
SqlDataAdapter da = new SqlDataAdapter(cmd);
con.Open();
DataSet ds = new DataSet();
da.Fill(ds);
return ds;
}
after returning the ds you will need to bind it like this
dataGridView1.DataSource = ds;
dataGridView1.DataBind();
I'm fairly certain that you're not getting any data because you're closing the connection before binding, and because you're using an incompatible type as your data source:
con.Close();
dataGridView1.DataSource = red;
Set the data source prior to closing the connection, or at least be sure to populate the data (for data readers, the data are populated as you enumerate). Additionally, DataGridView.DataSource indicates that it must use one of four interfaces: IList, IListSource, IBindingList, and IBindingListSource. SqlDataReader does not support these. I recommend reading DataAdapters and DataReaders, as this outlines some of the features that are for populating this kind of control.
I am pulling data from a sql server and putting it into a grid using c#. When the data displays on the grid, it is showing up as the guid rather than the actual name. How do I get the name to show and not the uniqe identifier. Any ideas? Thanks.
Here is some of the code:
public InventoryWindow()
{
InitializeComponent();
if (dgDataView != null)
{
SqlConnection con = new SqlConnection(connString);
SqlDataAdapter adpt = new SqlDataAdapter("select * from Item", con);
DataSet ds = new DataSet();
adpt.Fill(ds, "Item");
dgDataView.DataContext = ds;
//dgDataView.DataMember = "Item";
showdata();
}
}
private void showdata()
{
String connString = "server=server;database=database;user=user;password=password";
SqlConnection con = new SqlConnection(connString);
con.Open();
SqlCommand cmd = new SqlCommand("select * from Item", con);
SqlDataReader dr = cmd.ExecuteReader();
DataTable dt = new DataTable();
dt.Load(dr);
dgDataView.DataContext = dt;
con.Close();
}
You are using select * from Item and therefore returning all columns. You could just specify the columns you want in the Grid, in the order you want them. The grid by default has autocolumn generation on.
You can also specify the columns you want and what fields they map to using the columns DataMember values.
I figured this out, I just wrote my own query to display certain columns instead of automatically showing all of them.