Gridview not populating by datatable - asp.net

Question

Below is the code where The four columns("Challan Number","Proposal Number","CTS Number" and "Amount") is obtained from Sql-Database, and the ("Land" and "Ward") values are obtained from respective methods. The values obtaines are correct but still the "ChallanGridview" is not getting populated.
The datarow "dr1" gets populated with the correct required values, but the "ChallanGridview" doesn't shows anything.
public void FillChallanGrid()
{
string query = string.Empty;
string cs = ConfigurationManager.ConnectionStrings["ConStrg"].ConnectionString;
query = CtrlChallenSearch1.GetChallanQuery();
using(SqlConnection con=new SqlConnection(cs))
{
SqlDataAdapter da = new SqlDataAdapter(query,con);
DataSet ds = new DataSet();
da.Fill(ds,"entry");
int x = ds.Tables["entry"].Rows.Count;
DataTable dt = new DataTable();
dt.Columns.Add("Challan Number");
dt.Columns.Add("Proposal Number");
dt.Columns.Add("CTS Number");
dt.Columns.Add("Amount");
dt.Columns.Add("Land");
dt.Columns.Add("Ward");
for(int i=0;i<x;i++)
{
DataRow dr = ds.Tables["entry"].Rows[i];
DataRow dr1 = dt.NewRow();
dr1["Challan Number"] = dr["ReceiptNo"].ToString();
dr1["Proposal Number"] = dr["ProposalNo"].ToString();
dr1["CTS Number"] = dr["CTSNo"].ToString();
dr1["Amount"] = dr["Amount"].ToString();
dr1["Land"] = GetLand(dr["ProposalNo"].ToString());
dr1["Ward"]=GetWard(dr["ProposalNo"].ToString());
dt.Rows.Add(dr1);
}
ChallanGridView.DataSource = dt;
ChallanGridView.DataBind();
}
}
private object GetLand(string ProposalNumber)
{
string retvalue = string.Empty;
if (ProposalNumber != "" || ProposalNumber != null || ProposalNumber != string.Empty)
{
string[] splittedvalue = ProposalNumber.Split('/');
retvalue = splittedvalue[1];
}
return retvalue;
}
private object GetWard(string ProposalNumber)
{
string retvalue = string.Empty;
string[] splittedvalue = new string[3];
splittedvalue = ProposalNumber.Split('/');
retvalue = splittedvalue[0];
return retvalue;
}
protected void Button1_Click(object sender, EventArgs e)
{
FillChallanGrid();
}

Answer 1

Its solved, I just deleted the present gridview and added another fresh one,
don't know how and why, but the error was gone.
btw thnks Asif.Ali!