问如何在MVC中实现MB值和GB值字段的求和函数

EN

-- This is your "raw" input - just all the strings in your example
DECLARE @input TABLE (Measure VARCHAR(50))

INSERT INTO @input ( Measure )
VALUES ('810.9 MB'), ('1.2 GB'), ( '395.1 MB'), ( '982.3 MB'), ( '7.7 GB'), ( '149.4 MB'), ( '10.0 GB'), ( '429.1 MB'), ( '3.1 GB')

-- Now declare a separate table that contains (1) the raw value, (2) the contained *numerical* value, and (3) the unit of measure
DECLARE @Storage TABLE (Measure VARCHAR(50), NumValue DECIMAL(20,4), Unit VARCHAR(10))

-- Fill your raw input into that "working table"
INSERT INTO @Storage (Measure, NumValue, Unit)
    SELECT
        Measure,
        NumMeasure = CAST(SUBSTRING(Measure, 1, CHARINDEX(' ', Measure)) AS DECIMAL(20, 2)),
        Unit = SUBSTRING(Measure, CHARINDEX(' ', Measure) + 1, 9999)
    FROM 
        @input

SELECT * FROM @Storage

-- when you select from that "working" table, you can now easily *SUM* the numerical values,
-- and show them on screen whichever way you want - as "xxx MB" or "yyyy GB" or whatever - up to you
SELECT 
    SUM(CASE Unit   
           WHEN 'MB' THEN NumValue * 1000000
           WHEN 'GB' THEN NumValue * 1000000000
           ELSE NumValue
        END),
    CAST(SUM(CASE Unit   
           WHEN 'MB' THEN NumValue * 1000000
           WHEN 'GB' THEN NumValue * 1000000000
           ELSE NumValue
        END) / 1000000000.0 AS VARCHAR(25)) + ' GB'
FROM 
    @Storage

foreach(var item in list)
{
    // split "item" into two parts
    string[] parts = item.Split(' ');

    // parts[0] should be a decimal value
    decimal numValue = 0.0m;

    if (decimal.TryParse(parts[0], out numValue))
    {
        decimal convertedValue = 0.0m;

        if(parts[1] == "MB")
        {
            convertedValue = numValue * 1000000;
        }
        else if (parts[1] == "GB")
        {
            convertedValue = numValue * 1000000000;
        }
     }
}