C＃-从数据表以字符串形式返回单个值（任何数据类型）

Question

I've loaded a table from excel in C# using the ExcelDataReader package, however I'm struggling to write a method which returns the value of a cell as a string, based on the row number and column name.

I have a solution for a method that works if there are just strings in the DataTable...

public string ReadData(int rowNum, string columnName)
{
    DataRow row = table.Rows[rowNum];
    string value = row.Field<string>(columnName);
    return value;
}

(the DataTable variable 'table' is loaded elsewhere) ..however I would like also like to be able to return numbers and dates (as strings).

I feel I might need to edit this part somehow...

string value = row.Field<string>(columnName);

But I don't know how to make it so it pulls back whatever value and type is in that field and returns a string.

Many thanks!

Answer 1

您可以使用DataRow name-indexer返回一个object在该object上我们可以调用.ToString()将其转换为string 。

return row[columnname].ToString();

Answer 2

You can simply use the by-name-indexer and call ToString() :

string value = row[columnName].ToString();

You probably should check for null values:

string value = (row[columnName] ?? string.Empty).ToString();

Answer 3

Use

string value = Convert.ToString(row[columnName]);

Using Convert.ToString() is preferrable because it does not only check for null but also for DBNull , which is the value of the column when accessing a real database where the column has no content.

Answer 4

在C＃6.0中：

return row[columnName]?.ToString();