Add DataRow in DataTable

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Hi,

I have a datatable, and I am applying conditions to that.

C#

DataTable dt = new DataTable();
dt = (DataTable)Session["table"];
DataRow[] rows = dt.Select("Name = 'abc'");
dt.Clear();
dt.Rows.Add(rows);

When I add rows to datatable, I am getting an error,

Input array is longer than the number of columns in this table.

DataTable columns :

C#

if (Session["table"] != null)
{
        DataColumn col = new DataColumn();
        col.DataType = System.Type.GetType("System.Int32");
        col.ColumnName = "sno";
        DataTable dt = new DataTable();
        dt = (DataTable)Session["table"];
        if (!dt.Columns.Contains("RegNo"))
        {
                dt.Columns.Add("RegNo").SetOrdinal(6);
        }
        if (!dt.Columns.Contains(col))
        {
             dt.Columns.Add(col);
             col.SetOrdinal(0);
        }
        int index = 0;
        foreach (DataRow row in dt.Rows)
        {
               row.SetField(col, ++index);
        }
        DataRow[] rows = dt.Select("Name = 'abc'");
        dt.Clear();
        if (flag == 0)
        {
            foreach (DataRow row in dt.Rows)
            {
                row.SetField("RegNo", "null");
            }
            flag = 1;
         }
         dt.Rows.Add(rows);
         gd.Visible = true;
         gd.DataSource = dt;
         gd.DataBind();
}

Please help. Thanks in advance

Posted 20-Feb-14 23:35pm

srmohanr

Updated 20-Feb-14 23:56pm

Ahmed Bensaid

v2

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Comments

Faisalabadians 21-Feb-14 5:41am

Error is quite explaining. your data table has less columns then your new data row has columns.
make sure your number of columns in data table and new data row are same. Also look at column names, the should also be same.

srmohanr 21-Feb-14 5:42am

I have checked no. of columns in both DataTable and DataRow

Faisalabadians 21-Feb-14 5:46am

could you show your data table columns and row columns (source code) ?

srmohanr 21-Feb-14 5:53am

if (Session["table"] != null)
{
DataColumn col = new DataColumn();
col.DataType = System.Type.GetType("System.Int32");
col.ColumnName = "sno";
DataTable dt = new DataTable();
dt = (DataTable)Session["table"];
if (!dt.Columns.Contains("RegNo"))
{
dt.Columns.Add("RegNo").SetOrdinal(6);
}
if (!dt.Columns.Contains(col))
{
dt.Columns.Add(col);
col.SetOrdinal(0);
}
int index = 0;
foreach (DataRow row in dt.Rows)
{
row.SetField(col, ++index);
}
DataRow[] rows = dt.Select("Name = 'abc'");
dt.Clear();
if (flag == 0)
{
foreach (DataRow row in dt.Rows)
{
row.SetField("RegNo", "null");
}
flag = 1;
}
dt.Rows.Add(rows);
gd.Visible = true;
gd.DataSource = dt;
gd.DataBind();
}

srmohanr 21-Feb-14 5:55am

When dt.Clear() is executed, my rows[] also becoming null.

Faisalabadians 21-Feb-14 6:03am

dt.Clear() removes all rows from data table. why you calling this? else code seems to be working. how many total columns do you have when calling " dt.Columns.Add("RegNo").SetOrdinal(6);" ?

srmohanr 21-Feb-14 6:04am

I want to remove the existing data in datatable.

Faisalabadians 21-Feb-14 6:11am

"dt = (DataTable)Session["table"];" how many columns are there when you execute this code?

1 solution

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Ahmed Bensaid · Accepted Answer · 2014-02-21T00:07:00

Solution 1

http://social.msdn.microsoft.com/Forums/vstudio/en-US/f0753e31-efd0-44b8-b5a5-836e5f058420/remove-rows-from-datatable?forum=wpf[^]

Try to remove only the undesired rows :

C#

DataRow[] dr = null;//a datarow array
dr = dt.Select("Name != 'abc'"); //get the rows with matching condition in arrray
//loop throw the array and delete those rows from datatable
foreach (DataRow row in dr) {
    dt.Rows.Remove(row);
}

Posted 21-Feb-14 0:07am

Ahmed Bensaid

Comments

srmohanr 21-Feb-14 6:38am

Its showing me an error 'Cannot interpret token '!' at position 6.'

srmohanr 21-Feb-14 6:44am

I have changed the condition to
dr = dt.Select("Name <> 'abc'");
It is working fine.
Thanks for your help

Ahmed Bensaid 21-Feb-14 8:24am

Yes, sorry for the "!=" ;)
You're welcome !