C# – How to convert a String to a BlobColumn in SSIS

csql serverssis

So I have a column in my SSIS Script Called Data which is of type BlobColumn

I want to assign this column to a string value.

I do the following:

Row.Data = "MyString";

but I get the following error:

Cannot implicitly convert type 'string' to
Microsoft.SqlServer.Dts.Pipeline.BlobColumn

So how do I assign a BlobColumn to a String value?

Best Answer

using the answer provided for Converting a string to byte-array without using an encoding (byte-by-byte)

I did the following:

Row.Data.AddBlobData(GetBytes("MyString"));

Where:

byte[] GetBytes(string str)
{
    byte[] bytes = new byte[str.Length * sizeof(char)];
    System.Buffer.BlockCopy(str.ToCharArray(), 0, bytes, 0, bytes.Length);
    return bytes;
}

This is the style that Microsoft tends to use in their examples.

It appears that the guidance in this area may have changed, as StyleCop now enforces the use of the C# specific aliases.

C# – Convert a string to an enum in C#

In .NET Core and .NET Framework ≥4.0 there is a generic parse method:

Enum.TryParse("Active", out StatusEnum myStatus);

This also includes C#7's new inline out variables, so this does the try-parse, conversion to the explicit enum type and initialises+populates the myStatus variable.

If you have access to C#7 and the latest .NET this is the best way.

Original Answer

In .NET it's rather ugly (until 4 or above):

StatusEnum MyStatus = (StatusEnum) Enum.Parse(typeof(StatusEnum), "Active", true);

I tend to simplify this with:

public static T ParseEnum<T>(string value)
{
    return (T) Enum.Parse(typeof(T), value, true);
}

Then I can do:

StatusEnum MyStatus = EnumUtil.ParseEnum<StatusEnum>("Active");

One option suggested in the comments is to add an extension, which is simple enough:

public static T ToEnum<T>(this string value)
{
    return (T) Enum.Parse(typeof(T), value, true);
}

StatusEnum MyStatus = "Active".ToEnum<StatusEnum>();

Finally, you may want to have a default enum to use if the string cannot be parsed:

public static T ToEnum<T>(this string value, T defaultValue) 
{
    if (string.IsNullOrEmpty(value))
    {
        return defaultValue;
    }

    T result;
    return Enum.TryParse<T>(value, true, out result) ? result : defaultValue;
}

Which makes this the call:

StatusEnum MyStatus = "Active".ToEnum(StatusEnum.None);

However, I would be careful adding an extension method like this to string as (without namespace control) it will appear on all instances of string whether they hold an enum or not (so 1234.ToString().ToEnum(StatusEnum.None) would be valid but nonsensical) . It's often be best to avoid cluttering Microsoft's core classes with extra methods that only apply in very specific contexts unless your entire development team has a very good understanding of what those extensions do.

Best Answer

Related Solutions

C# – the difference between String and string in C#

This is the style that Microsoft tends to use in their examples.

C# – Convert a string to an enum in C#

Original Answer

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