Durga Durga - 1 month ago 10
C# Question

Error : Update requires a valid UpdateCommand when passed DataRow collection with modified rows

I am using Paging to show data in

datagridview
, but when i try to Update any data with
updatebutton
data should be updated In
datagridview
as well as in database.

But I get this error:


Update requires a valid UpdateCommand when passed DataRow collection
with modified rows


which happens on this line:

adp1.Update(dt);//here I am getting error


Below is the code

public partial class EditMediClgList : Form
{
public EditMediClgList()
{
InitializeComponent();
try
{
con = new OleDbConnection(@"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=db1.mdb");
con.Open();
}
catch (Exception err)
{
MessageBox.Show("Error:" +err);
}

cmd1 = new OleDbCommand("Select * from MedicalColeges order by MedicalClgID", con);
ds = new DataSet();
adp1 = new OleDbDataAdapter(cmd1);
adp1.Fill(ds, "MedicalColeges");
dataGridView1.DataSource = ds;

// Get total count of the pages;
this.CalculateTotalPages();
// Load the first page of data;
this.dataGridView1.DataSource = GetCurrentRecords(1, con);

}
private void CalculateTotalPages()
{
int rowCount = ds.Tables["MedicalColeges"].Rows.Count;
this.TotalPage = rowCount / PageSize;
if (rowCount % PageSize > 0) // if remainder is more than zero
{
this.TotalPage += 1;
}
}
private DataTable GetCurrentRecords(int page, OleDbConnection con)
{
dt = new DataTable();

if (page == 1)
{
cmd2 = new OleDbCommand("Select TOP " + PageSize + " * from MedicalColeges ORDER BY MedicalClgID", con);
// CurrentPageIndex++;
}
else
{
int PreviouspageLimit = (page - 1) * PageSize;

cmd2 = new OleDbCommand("Select TOP " + PageSize +
" * from MedicalColeges " +
"WHERE MedicalClgID NOT IN " +
"(Select TOP " + PreviouspageLimit + " MedicalClgID from MedicalColeges ORDER BY MedicalClgID) ", con); // +
//"order by customerid", con);
}
try
{
// con.Open();
this.adp1.SelectCommand = cmd2;
this.adp1.Fill(dt);
txtPaging.Text = string.Format("page{0} of {1} pages", this.CurrentPageIndex, this.TotalPage);
}
finally
{
// con.Close();
}
return dt;
}

private void button1_Click(object sender, EventArgs e)
{
try
{
adp1.Update(dt);//here I am getting error
}
catch (Exception err)
{
MessageBox.Show(err.Message.ToString());
}

}
}

Answer

You have Created the OleDbDataAdapter with a Select command only:

adp1 = new OleDbDataAdapter(cmd1);

OleDbDataAdapter requires valid Update, Insert, Delete commands to be used to save the data like this:

adp1.Update(dt);//here I am getting error

You just need to use a OleDbCommandBuilder that will generate the commands for you:

adp1 = new OleDbDataAdapter();
adp1.SelectCommand = cmd1; // cmd1 is your SELECT command
OleDbCommandBuilder cb = new OleDbCommandBuilder(adp1);

EDIT

Since you change the Select command of the OleDbDataAdapter at runtime for paging, what your need is to initialize each time you save data:

private void button1_Click(object sender, EventArgs e)
    {
        try
        {                
            adp1.SelectCommand = cmd1; // cmd1 is your SELECT command
            OleDbCommandBuilder cb = new OleDbCommandBuilder(adp1);
            adp1.Update(dt); //here I hope you won't get error :-)
        }
        catch (Exception err)
        {
            MessageBox.Show(err.Message.ToString());
        }

    }