I want to print repeated date of data table once and then after that date found next time it should be empty value

See more:

C#

I have data table in C# and in that I have multiple column in that date column contain repeated date for multiple rows so I have arranged data date desc now i want to print date if date is repeated then it should come with empty value

I have data table data as

#          Challan Date  Item Name   Item Code   UMO

CHWe216495	   10/Mar/2018          TABLE             ppppp           44cvc
CHWe216495	   10/Mar/2018          TABLE SHARP       qqqq            211dd
CHWe216495         10/Mar/2018          TABLE SHARPNER    rrrr             54lo 
CHWe216496         11/Mar/2018          TABLE E M.S SOFF  mmmm             1235
CHWe216496         11/Mar/2018          TABLE SHARPENER - nnnn             p123
CHWe216496         11/Mar/2018          TABLE SHARPNER    asdf             mop12
and so on

I am displaying this data in table for that I created string in which i created table using string builder now I want data as following

<pre><pre>   #	      Challan Date	Item Name	Item Code	UMO

CHWe216495	   10/Mar/2018          TABLE             ppppp           44cvc
CHWe216495	                        TABLE SHARP       qqqq            211dd
CHWe216495                              TABLE SHARPNER    rrrr             54lo 
CHWe216496         11/Mar/2018          TABLE E M.S SOFF  mmmm             1235
CHWe216496                              TABLE SHARPENER - nnnn             p123
CHWe216496                              TABLE SHARPNER    asdf             mop12

but it is showing data as in my solution

<pre><pre>   #	      Challan Date	Item Name	Item Code	UMO

CHWe216495	   10/Mar/2018          TABLE             ppppp           44cvc
CHWe216495	                        TABLE SHARP       qqqq            211dd
CHWe216495         10/Mar/2018          TABLE SHARPNER    rrrr             54lo 
CHWe216496         11/Mar/2018          TABLE E M.S SOFF  mmmm             1235
CHWe216496                              TABLE SHARPENER - nnnn             p123
CHWe216496         11/Mar/2018          TABLE SHARPNER    asdf             mop12

which is incorrect please provide solution

What I have tried:

string StrprevChallanDate=string.empty;
if (dtJobWork4 != null)
                    {

                        for (int i = 0; i < dtJobWork4.Rows.Count; i++)
                        {
                           
                            if (dtJobWork4.Rows[i]["ChallanDate"] != null)
                            {
                                StrChallanDate = DateTime.Parse(dtJobWork4.Rows[i]["ChallanDate"].ToString()).ToString("dd/MMM/yyyy");
                                //strODate = DateTime.Parse(dtJobWork1.Rows[i]["OrderDate"].ToString()).ToString("dd/MMM/yyyy");
                            }
                            if (StrprevChallanDate != "")
                            {
                                if (StrprevChallanDate != StrChallanDate)
                                {
                                    //Flag = 1;
                                    StrChallanDate = DateTime.Parse(dtJobWork4.Rows[i]["ChallanDate"].ToString()).ToString("dd/MMM/yyyy");
                                }
                                else
                                {
                                    StrChallanDate = "";
                                }
                            }

                            if (dtJobWork4.Rows[i]["ItemId"] != null)
                            {
                                StrItemId = dtJobWork4.Rows[i]["ItemId"].ToString();
                            }
                            if (dtJobWork4.Rows[i]["ItemName"] != null)
                            {
                                StrItemName = dtJobWork4.Rows[i]["ItemName"].ToString();
                            }
                            StrItemName = funSplit(StrItemName, 20);
                            if (dtJobWork4.Rows[i]["ItemCode"] != null)
                            {
                                StrItemCode = dtJobWork4.Rows[i]["ItemCode"].ToString();
                            }
                            if (dtJobWork4.Rows[i]["HSNCode"] != null)
                            {
                                StrHSNCode = dtJobWork4.Rows[i]["HSNCode"].ToString();
                            }
                            if (dtJobWork4.Rows[i]["UOM"] != null)
                            {
                                StrUOM = dtJobWork4.Rows[i]["UOM"].ToString();
                            }
                            if (dtJobWork4.Rows[i]["Qty"] != null)
                            {
                                strtbl4quantity = dtJobWork4.Rows[i]["Qty"].ToString();
                                //StrQty = Convert.ToDecimal(dtJobWork4.Rows[i]["Qty"]);
                            }
                            if (dtJobWork4.Rows[i]["Rate"] != null)
                            {
                                strtbl4Rate = dtJobWork4.Rows[i]["Rate"].ToString();
                                //StrRate = Convert.ToDecimal(dtJobWork4.Rows[i]["Rate"]);
                            }

                            if (dtJobWork4.Rows[i]["Amount"] != null)
                            {
                                strtbl4Amount = dtJobWork4.Rows[i]["Amount"].ToString();
                                //StrRate = Convert.ToDecimal(dtJobWork4.Rows[i]["Amount"]);
                            }

                                                       
                            strLblTbl.Append("<table cellspacing='0' cellpadding='0' style='width:800px; border-bottom:none; border-left:solid 1px silver; border-right:solid 1px silver'>");
                            strLblTbl.Append("<tr>");
                            
                            
                                strLblTbl.Append("<td style= 'height:18px;width:90px; border-bottom:solid 1px silver;  border-right:solid 1px silver;text-indent:5px; ' align = 'left'>" + StrChallanId + "</td>");
                                strLblTbl.Append("<td style=' height:18px;width:100px; border-bottom:solid 1px silver;  border-right:solid 1px silver;' align = 'left'><div style='margin-left:5px;'>" + StrChallanDate + "</div></td>");
                                strLblTbl.Append("<td style=' height:18px;width:150px; border-bottom:solid 1px silver;  border-right:solid 1px silver;' align = 'left'><div style='margin-left:5px;'>" + StrItemName + "</div></td>");
                                strLblTbl.Append("<td style=' height:18px;width:70px; border-bottom:solid 1px silver;  border-right:solid 1px silver; text-indent:5px;' align = 'left'>" + StrItemCode + "</td>");
                                strLblTbl.Append("<td style=' height:18px;width:70px; border-bottom:solid 1px silver;  border-right:solid 1px silver; text-indent:5px;' align = 'left'>" + StrUOM + "</td>");
			        strLblTbl.Append("<td style=' height:18px;width:80px; border-bottom:solid 1px silver;  border-right:solid 1px silver;text-indent:5px; ' >" + StrHSNCode + "  </td>");
                                strLblTbl.Append("<td style=' height:18px;width:80px; border-bottom:solid 1px silver;  border-right:solid 1px silver;text-indent:5px;' align = 'right'>" + currencyConverter(Math.Abs(Dectbl4Qty)) + "  </td>");
                                strLblTbl.Append("<td style=' height:18px;width:80px; border-bottom:solid 1px silver;  border-right:solid 1px silver;text-indent:5px; ' align = 'right'>" + currencyConverter(GetTwoDecimalValue(Math.Abs(Dectbl4Rate))) + "  </td>");
                                strLblTbl.Append("<td style=' height:18px;width:80px; border-bottom:solid 1px silver;text-indent:5px;' align = 'right'>" + currencyConverter(Math.Abs(Dectbl4Amount)) + "  </td>");

                           
                            strLblTbl.Append("</tr>");

                            strLblTbl.Append("</table>");
                           

                            StrprevChallanDate = StrChallanDate;
                        }
}