//set to the ID of the grid:
var gridId = "g2";  
//set to the column number of field to check whether to show/hide the delete button:
var fieldColNo = 4;

//regular expression to get grid row number in form.setOnchange():
var gridRE = new RegExp('^\\['+gridId+'\\]\\[(\\d+)\\]'); 

//function that hides the "Delete" button in the grid's rowNumber 
//if the "cost" field is over 100. Otherwise, it shows the button.
//If the rowNumber is set to 0, then all the rows in the grid will be checked  
function showHideDeleteButtonsInGrid(rowNumber) {
  var oGrid = $("#"+gridId);
  
  if (rowNumber < 1) {
    var nRows = oGrid.getNumberRows();
    
    for (var i = 1; i <= nRows; i++) {
      var cost = parseFloat( oGrid.getValue(i, fieldColNo) );
     
      if (!isNaN(cost) && cost >= 100) {
        $("div.pmdynaform-grid-removerow-responsive").eq(i-1).find("button").hide();    
      }
      else {
        $("div.pmdynaform-grid-removerow-responsive").eq(i-1).find("button").show();    
      }    
    }
  }
  else {
    var cost = parseFloat( oGrid.getValue(rowNumber, fieldColNo) );
    
    if (!isNaN(cost) && cost >= 100) {
      $("div.pmdynaform-grid-removerow-responsive").eq(rowNumber-1).find("button").hide();    
    }
    else {
      $("div.pmdynaform-grid-removerow-responsive").eq(rowNumber-1).find("button").show();    
    } 
  }  
}

//execute when dynaform loads to hide/show Delete buttons in
//every row in the grid:
showHideDeleteButtonsInGrid(0);

//change event handler for all fields in Dynaform, which only looks
//for changes in the grid:
$( "#"+$("form").prop("id") ).setOnchange( function(fieldName, newVal, oldVal) {
  var oGrid = $("#"+gridId);
  var aMatch = fieldName.match(gridRE);

  if (aMatch !== null) {
    var rowNo = parseInt(aMatch[1]);
    showHideDeleteButtonsInGrid(rowNo);
  }
})

در مثال فوق قرار است کالاهایی که مقدار ستون هزینه آنها از 100 بیشتر باشد کاربر مجاز به حذفشان نباشد و دکمه سطل آشغال انتهای گرید مخفی شود