Issue while deleting row using DataSet

问题

Following code does not delete a row from dataset and dont update the database....

string cs = ConfigurationManager.ConnectionStrings["DBCS"].ConnectionString;
                SqlConnection con = new SqlConnection();
                con.ConnectionString = cs;
                SqlDataAdapter adpt = new SqlDataAdapter("Select *from RegisterInfoB", con);
                ds = new DataSet();
                adpt.Fill(ds, "RegisterTable");
                foreach (DataRow dr in ds.Tables[0].Rows)
                {
                    if (dr["FirstName"] == "praveen")
                    {
                        dr.Delete();
                    }
                }
                ds.Tables[0].AcceptChanges();

How to resolve this problem...How do I update my sql server database...by deleting a row from dataset..

回答1:

I hope this will work for you:

string cs = ConfigurationManager.ConnectionStrings["DBCS"].ConnectionString;
            SqlConnection con = new SqlConnection();
            con.ConnectionString = cs;
            SqlDataAdapter adpt = new SqlDataAdapter("Select * from RegisterInfoB", con);
            DataSet ds = new DataSet();
            adpt.Fill(ds, "RegisterTable");
            foreach (DataRow dr in ds.Tables[0].Rows)
            {
                if (dr["FirstName"].ToString().Trim() == "praveen")
                {
                    dr.Delete();

                }
            }
            adpt.Update(ds);

Two Changes
1st: if (dr["FirstName"].ToString().Trim() == "praveen") trimming the blank spaces in your db's FirstName Field.
2nd : use adpt.Update(ds); to update your DB.

Another Way to doing it:

string cs = ConfigurationManager.ConnectionStrings["DBCS"].ConnectionString;
                SqlConnection con = new SqlConnection();
                con.ConnectionString = cs;
                string firstName= "praveen"; // this data will get from calling method
                SqlDataAdapter adpt = new SqlDataAdapter("Select * from RegisterInfoB", con);
                DataSet ds = new DataSet();
                adpt.Fill(ds, "RegisterTable");
                string deleteQuery = string.Format("Delete from RegisterInfoB where FirstName = '{0}'", firstName);
                SqlCommand cmd = new SqlCommand(deleteQuery, con);
                adpt.DeleteCommand = cmd;
                con.Open();
                adpt.DeleteCommand.ExecuteNonQuery();
                con.Close();

Similary, you can write query for UpdateCommand and InsertCommand to perform Update and Insert Respectively.

回答2:

Find rows based on specific column value and delete:

DataRow[] foundRows;
foundRows = ds.Tables["RegisterTable"].Select("FirstName = 'praveen'");
foundRows.Delete();

EDIT: Adding a DeleteCommand to the data adapter (based on example from MSDN)

Note: Need an Id field here instead of FirstName, but I don't know your table structure for RegisterInfoB. Otherwise, we delete everyone named "praveen".

// Create the DeleteCommand.
command = new SqlCommand("DELETE FROM RegisterInfoB WHERE FirstName = @FirstName", con);

// Add the parameters for the DeleteCommand.
parameter = command.Parameters.Add("@FirstName", SqlDbType.NChar, 25, "FirstName");
parameter.SourceVersion = DataRowVersion.Original;

// Assign the DeleteCommand to the adapter
adpt.DeleteCommand = command;

To update a database with a dataset using a data adapter:

try
{
    adpt.Update(ds.Tables["RegisterTable"]);
}
catch (Exception e)
{
    // Error during Update, add code to locate error, reconcile  
    // and try to update again.
}

Sources: https://msdn.microsoft.com/en-us/library/xzb1zw3x(v=vs.120).aspx https://msdn.microsoft.com/en-us/library/y06xa2h1(v=vs.120).aspx

回答3:

hope that resolve the problem, Try it:

        var connectionString = ConfigurationManager.ConnectionStrings["DBCS"].ConnectionString;
        var selectQuery = "Select * from RegisterInfoB";

        SqlConnection connection = new SqlConnection(connectionString);
        SqlCommand selectCommand = new SqlCommand(selectQuery, connection);
        SqlDataAdapter adapter = new SqlDataAdapter(selectCommand);

        SqlCommandBuilder builder = new SqlCommandBuilder(adapter);

        DataSet dataSet = new DataSet();        

        // you can use the builder to generate the DeleteCommand
        adapter.DeleteCommand = builder.GetDeleteCommand();
        // or 
        // adapter.DeleteCommand = new SqlCommand("DELETE FROM RegisterInfoB WHERE Id= @Id", connection);

        adapter.Fill(dataSet, "RegisterInfoB");

        // you can use the foreach loop 

        foreach (DataRow current in dataSet.Tables["RegisterInfoB"].Rows)
        {
            if (current["FirstName"].ToString().ToLower() == "praveen")
            {
                current.Delete();
            }
        }

        // or the linq expression 

        // dataSet.Tables["RegisterInfoB"]
        //    .AsEnumerable()
        //    .Where(dr => dr["FirstName"].ToString().ToLower().Trim() == "praveen")
        //    .ToList()
        //    .ForEach((dr)=> dr.Delete());

        var result = adapter.Update(dataSet.Tables["RegisterInfoB"]);

also you can add some events and put a breakpoint to see if the state is changing or if there is an error that prevent changes on the source:

        dataSet.Tables["RegisterInfoB"].RowDeleted += (s, e) =>
        {
            var r = e.Row.RowState;
        };

        dataSet.Tables["RegisterInfoB"].RowDeleting += (s, e) =>
        {
            var r = e.Row.RowState;
        };

来源：https://stackoverflow.com/questions/32830618/issue-while-deleting-row-using-dataset