如何将空列替换为“ND”使用ASP.NET C＃？ [英] How to replace empty column as "ND" using ASP.NET C#?

问题描述

我想将数据集数据表中特定空列的值设置为数据集中的ND。

怎么做？



我尝试了什么：

I want to set value for particular empty column in data set data table as "ND" in data set.
How to do it?

What I have tried:

if (ds.Tables[s].Rows[i][Columncountvalue + 19].ToString().Trim() == "")
{
 ds.Tables[s].Rows[i][Columncountvalue + 19].ToString().Trim().Replace("", "ND");
}

上面的代码是我试图在数据集数据表中将空列填充为ND但是发生以下错误



字符串长度不能为零。参数名称oldvalue

the above code is i tried to fill the empty column as "ND" in dataset data table but below error is occurs

string cannot be of zero length. parameter name oldvalue

推荐答案

您好，



怎么样：

Hi,

How about this :

private void UpdateNulls (DataTable dataTable){
    List<string> dcNames = dataTable.Columns
                            .Cast<DataColumn>()
                            .Select(x => x.ColumnName)
                            .ToList(); //This querying of the Column Names, you could do with LINQ
    foreach (DataRow row in dataTable.Rows) //This is the part where you update the cell one by one
        foreach (string columnName in dcNames)
            row[columnName] = string.IsNullOrEmpty(Convert.ToString(row[columnName])) ? "ND" : row[columnName];
}

我建​​议在服务器级别上这样做，因为它总是比在客户端更快。



所有你需要做的，就是编写类似这样的查询：

I'd suggest to do that on server level, because it is always faster than on client side.

All you need to do, is to write query similar to this:

SELECT Field1, Field2, Field3 = CASE WHEN RTRIM(LTRIM(Field3)) = '' THEN 'ND' ELSE Field3 END
FROM YourTableName

现在，你必须创建存储过程 [ ^ ]（SP）并将该SP称为返回所需的结果集。怎么样？请检查：演练：仅使用存储过程（C＃） [ ^ ]



只使用存储过程有很多好处，例如保护 SQL注入 [ ^ 。请参阅：如何：保护ASP.NET中的SQL注入 [ ^ ]



试试！

Now, you have to create stored procedure[^] (SP) and call that SP to return desired result set. How? Check this: Walkthrough: Using Only Stored Procedures (C#)[^]

There's lot of benefits of using only stored procedures, such as protection of SQL Injection[^]. See: How To: Protect From SQL Injection in ASP.NET[^]

Try!

这篇关于如何将空列替换为“ND”使用ASP.NET C＃？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！