c# - Remove duplicate value in gridview rows -

i have seen question asked , answered before none of answers helped me. want when insert value textbox pressing button, if value exists in gridview removed or not inserted @ all.

my code:

protected void buton1_click(object sender, eventargs e) {     datatable dt = null;      if (session["griddata"] == null)     {         dt = new datatable();         datacolumn dc = new datacolumn("name");         dt.columns.add(dc);     }     else     {         dt = session["griddata"] datatable;     }      datarow dr = dt.newrow();     dr["name"] = textbox1.text;     dt.rows.add(dr);     dt.acceptchanges();     gridview1.datasource = dt;     gridview1.databind();     session["griddata"] = dt; } 

its better first check value exist or not in table , insert table.

var data = (from row in dt.asenumerable()             row.field<string>("name") == textbox1.text            select   row).tolist(); if(data != null && data.count > 0) {   //insert new row in table  } 

or

var data = (from row in dt.asenumerable()             select   row).            firstodefault(row=>row.field<string>                   ("name") == textbox1.text); if(data != null ) {   //insert new row in table  }