How to bind DataGridView from Database after selecting value from combox

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I am making a Windows Form in C#.I have a DataGridView and a combobox, all I want to do is if i select a table in the combobox, it should display me the results in the datagridview.

I have done something like this: BUT i' m getting this error : 'System.Data.DataRowView' does not contain a definition

C#

private void cbTbl_SelectedIndexChanged(object sender, EventArgs e)
       {
           if (cbTbl.SelectedValue != null)
           {
               // Sql Server Connection and statement if a value is selected

               string CS = ConfigurationManager.ConnectionStrings["DBCS"].ConnectionString;
               SqlConnection con = new SqlConnection(CS);
               SqlCommand sqlCmd = new SqlCommand();
               sqlCmd.Connection = con;
               sqlCmd.CommandType = CommandType.Text;
               sqlCmd.CommandText = ("SELECT * FROM " + cbTbl.SelectedValue); // Dynamically
               SqlDataAdapter sqlDataAdap = new SqlDataAdapter(sqlCmd);

               try
               {
                   con.Open();

                   dt = new DataTable();
                   sqlDataAdap.Fill(dt);
                   dataGridView1.AutoGenerateColumns = true;
                   dataGridView1.DataSource = dt;

               dataGridView1.AutoResizeColumns(DataGridViewAutoSizeColumnsMode.AllCells);

                   con.Close();

               }
               catch (Exception ex)
               {
                   MessageBox.Show(ex.Message);
               }
           }

I need to cast the SelectedItem into DataRowView in order to get a value from this DataRowView But i don't know where and how.

I'm filling the combobox with this method:

C#

private void FillCombobox1()
{
// Sql Connection and statement
string C = (@"Data Source=");
SqlConnection con = new SqlConnection(C);


SqlCommand cmd = new SqlCommand();
cmd.Connection = con;
cmd.CommandText = ("SELECT TABLE_NAME FROM INFORMATION_SCHEMA.TABLES");
try
{

con.Open();

SqlDataAdapter adapter = new SqlDataAdapter(cmd);

DataTable dt = new DataTable();
adapter.Fill(dt);

//Fill combobox with data in DT
comboBox1.DataSource = dt;

//Display dbo Tables in cbAlt
comboBox1.DisplayMember = "TABLE_NAME";
comboBox1.ValueMember = "TABLE_NAME";

// Empty bzw. clear the combobox
comboBox1.SelectedIndex = -1;

}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
finally
{
con.Close();
}
}

Posted 10-Nov-14 0:48am

mikybrain1

Updated 10-Nov-14 3:36am

v4

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Comments

Herman<T>.Instance 10-Nov-14 7:33am

In which line you get the exception?

mikybrain1 10-Nov-14 9:08am

HiIt doesn't really indicate which line. It' a message box clue :)

Sinisa Hajnal 10-Nov-14 9:22am

Set a breakpoint at the start of the method and step through the code.

Sinisa Hajnal 10-Nov-14 7:36am

How are you filling your cbTbl? How are you setting its valueMember?

mikybrain1 10-Nov-14 9:04am

I'm filling it with a self made method:
private void FillCombobox1()
{
// Sql Connection and statement
string C = (@"Data Source=");
SqlConnection con = new SqlConnection(C);

SqlCommand cmd = new SqlCommand();
cmd.Connection = con;
cmd.CommandText = ("SELECT TABLE_NAME FROM INFORMATION_SCHEMA.TABLES");
try
{

con.Open();

SqlDataAdapter adapter = new SqlDataAdapter(cmd);

DataTable dt = new DataTable();
adapter.Fill(dt);

//Fill combobox with data in DT
comboBox1.DataSource = dt;

//Display dbo Tables in cbAlt
comboBox1.DisplayMember = "TABLE_NAME";
comboBox1.ValueMember = "TABLE_NAME";

// Empty bzw. clear the combobox
comboBox1.SelectedIndex = -1;

}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
finally
{
con.Close();
}
}
Can u help?

Sinisa Hajnal 10-Nov-14 9:21am

Please use Improve Question link, rather then posting code in comments. Thank you. I'll check it later today.

mikybrain1 10-Nov-14 9:26am

ok. Thnx

Sinisa Hajnal 10-Nov-14 9:25am

Look for SelectedItem in your code. Maybe you have data grid view handler somewhere (onEnter, OnLeave, RowValidating or some such) that is triggered with setting of DataSource...and since no row is selected the code fails.

You don't know WHERE the error is and you posted combobox handler because it uses SelectedVALUE, but that is not the same.

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Pikoh · Accepted Answer · 2014-11-10T03:38:00

Well,that's a common error. When you fill the combobox, set the DisplayMember and ValueMember before binding the data. Like this:

C#

//Display dbo Tables in cbAlt
comboBox1.DisplayMember = "TABLE_NAME";
comboBox1.ValueMember = "TABLE_NAME";
//Fill combobox with data in DT
comboBox1.DataSource = dt;

The problem you have is because when you bind the data with comboBox1.DataSource = dt, the comboBox1.SelectedIndexChanged is fired. But as the valueMember is still not set, what is passed to the event is a DataRowView,causing the error.

Edit

If you want to prevent to load the grid when you bind the data to the combo,do something like this:

C#

bool firstLoad=true;
.
.
.

private void cbTbl_SelectedIndexChanged(object sender, EventArgs e)
        {
            if (!firstLoad)
            {
              if (cbTbl.SelectedValue != null)  
              {  
                // Sql Server Connection and statement if a value is selected

                string CS = ConfigurationManager.ConnectionStrings["DBCS"].ConnectionString;
                SqlConnection con = new SqlConnection(CS);
                SqlCommand sqlCmd = new SqlCommand();
                sqlCmd.Connection = con;
                sqlCmd.CommandType = CommandType.Text;
                sqlCmd.CommandText = ("SELECT * FROM " + cbTbl.SelectedValue); // Dynamically
                SqlDataAdapter sqlDataAdap = new SqlDataAdapter(sqlCmd);
 
                try 
                {
                    con.Open();
                   
                    dt = new DataTable();
                    sqlDataAdap.Fill(dt);
                    dataGridView1.AutoGenerateColumns = true;
                    dataGridView1.DataSource = dt;
                    
                dataGridView1.AutoResizeColumns(DataGridViewAutoSizeColumnsMode.AllCells);
                    
                    con.Close();
                   
                }
                catch (Exception ex)
                {
                    MessageBox.Show(ex.Message);
                }
             }
           }
           else
           {
             firstLoad=false;
           }
       }

That is,use a boolean variable to prevent loading the datagrid view when the combobox data is binded.