c＃使用asp.net显示GridView页脚中的列总数

Question

I need display sum of Columns total ( Grand Total ) in GridView Footer in ASP.Net using C#.

I have two problems:

1. I can't apply the css style in GridView Footer ;
2. I have error

Specified cast is not valid.

when add the Sum of Tot2.

How to resolve this?

Thank you advance for any help.

This is SQL query:

        sql = " SELECT ZN, ";
        sql += "    IFNULL(Tot1,0) AS Tot1, ";
        sql += "    IFNULL(Tot2,0) AS Tot2 ";
        sql += " FROM ";
        sql += "    doTable ";
        sql += " ORDER BY ";
        sql += "    Tot1 DESC; ";

+----+------+------+
| Zn | Tot1 | Tot2 |
+----+------+------+
| ZO |    3 |    0 |
| ZO |    3 |    0 |
| ZO |    2 |    1 |
| ZO |    2 |    0 |
| ZO |    2 |    0 |
| ZO |    2 |    0 |
| ZO |    2 |    0 |
| ZO |    1 |    0 |
| ZO |    1 |    1 |
| ZO |    1 |    0 |
+----+------+------+
10 rows in set

This the code-behind :

OdbcDataAdapter adapter = new OdbcDataAdapter(command);
adapter.Fill(dsProducts);

gvProducts.Columns[1].FooterText = "Total";
gvProducts.Columns[2].ItemStyle.HorizontalAlign = HorizontalAlign.Right;
gvProducts.Columns[2].ItemStyle.CssClass = "ddl_Class_new";
gvProducts.Columns[2].FooterText = dsProducts.Tables[0].AsEnumerable().Select(x => x.Field<Int32>("Tot1")).Sum().ToString();

gvProducts.Columns[3].ItemStyle.HorizontalAlign = HorizontalAlign.Right;
gvProducts.Columns[3].ItemStyle.CssClass = "ddl_Class_new";
gvProducts.Columns[3].FooterText = dsProducts.Tables[0].AsEnumerable().Select(x => x.Field<Int32>("Tot2")).Sum().ToString();

Answer 1

First, you set the css of the footer with FooterStyle.CssClass

gvProducts.Columns[3].FooterStyle.CssClass = "ddl_Class_new";

And specified cast means that there are fields in Tot1 or Tot2 that are not convertible to Int32 . Probably because you use IFNULL in your query, change that to ISNULL if you use MS SQL or check if the data in aspnet is what you actually expect it to be by debugging.