Remove a datatable column

Israel

Hi!

I wrote this code to try to remove the "FirstName" column. Curiosly, I receive this error. Please could you have a look?

OleDbConnection conn = new OleDbConnection(@"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\Users\Research\Documents\Windows_Application_Samples\Rename_Column_Tablename\WindowsFormsApplication1\App_Data\visa.mdb;Persist Security Info=False");

DataTable table = new DataTable();

table.Columns.Add("name", typeof(int));

table.Columns.Add("function", typeof(string));

table.Columns.Add("date", typeof(DateTime));

table.Columns.Add("FirstName", typeof(string));*/

DataColumn column;

for (int i = 0; i < table.Columns.Count; i++)

{

column = table.Columns[i];

MessageBox.Show(column.ColumnName, i.ToString());

}

table.Columns["FirstName"].SetOrdinal(1);

for (int i = 0; i < table.Columns.Count; i++)

{

column = table.Columns[i];

MessageBox.Show(column.ColumnName, i.ToString());

}

9 Replies

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Vincent Maverick Durano11y ago
I would suggest you to debug your code. Set a break point and then step into it to figure out why it doesn't remove the column.
Israel11y ago
@Vincent
Your codes doesnt work and doesnt give buggs.
Nothing its happening when running and its doesnt remove any column as needed.
Vincent Maverick Durano11y ago
As i mentioned in my first post, you need to use the Remove or RemoveAt method. For example:

for (int i = 0; i < table.Columns.Count; i++){
column = table.Columns[i];
if(column.ColumnName.Equals("FirstName")){
table.Columns.RemoveAt(i);
break;
}
}
Israel11y ago
huuuuuuuuuuuuum, it's true. Then which solution now?
Vincent Maverick Durano11y ago
You are not removing a column. You are actually deleting the data.
Israel11y ago
See what I do. I just change the strategy. But its doesnt remove the column I need (no error message. Just nothing).

using (var con = new OleDbConnection(ConfigurationSettings.AppSettings[@"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\Users\Research\Documents\Windows_Application_Samples\Rename_Column_Tablename\WindowsFormsApplication1\App_Data\visa.mdb;Persist Security Info=False"]))
using(var cmd = new OleDbCommand())
{
cmd.CommandText = "DELETE empresa FROM test";
cmd.Connection = con;
con.Open();
int numberDeleted = cmd.ExecuteNonQuery(); // all rows deleted
Vincent Maverick Durano11y ago
I don't see a code for removing the column. You should use either of these:

table.Columns.Remove("columnName");
table.Columns.RemoveAt(columnIndex);
Israel11y ago
Sorry, Its doesnt do nothing.
Just looping (showing field name in box message).
When you get in the table there is no column removed.
Afzaal Ahmad Zeeshan11y ago
Which error? You forgot to mention the error's text here.