How to add all the row data of gridview to database?

Try this. In Button_Click() Event()

 SqlCommand cmd ;
           SqlConnection oConn = new SqlConnection(" Your Connection String "); 


           oConn.Open();
           cmd.Connection = oConn;
           cmd.CommandType = CommandType.Text;

        int n=0 ;  //get how many rows are added at end of insert


            foreach (DataRow dr in GridView1.Rows)
            { 
          cmd = new SqlCommand("Insert Into Tablename values (@Value1, @Value2)"); //Insert Query

     //Give Your Column name or use as   dr.rows.cell[index] 
    cmd.parameter["@Value1"].value = dr["GridViewColumnName"];  
                            cmd.parameter["@Value2"].value = dr["GridViewColumnName"];
                            n += cmd.ExecuteNonQuery();
      cmd.parameter.clear();
            }
            oConn.Close();

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Thank You

        Dim dgqty As New TextBox
        Dim hdpdtcid As New TextBox
 For Each dg As GridViewRow In grdDematChk.Rows
                    dgqty = dg.FindControl("TextBox1")
                    hdpdtcid = dg.FindControl("TextBox2")

                    //write  insert statement  here you can get text as  dgqty .Text
                 End If
     Next

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