Dynamically create an array of Type in C#

Question

In C#, I need to be able to create an array of Type objects at run-time based on a comma-delimited list of data types passed in to a function as a string. Basically, here is what I am trying to accomplish:

// create array of types
Type[] paramTypes = { typeof(uint), typeof(string), typeof(string), typeof(uint) };

But I need to be able to call my function like this:

MyFunction("uint, string, string, uint");

and have it generate the array dynamically based on the string passed in. Here was my first attempt:

void MyFunction(string dataTypes)
{
    //out or in parameters of your function.   
    char[] charSeparators = new char[] {',', ' '};
    string[] types = dataTypes.Split(charSeparators,
                        stringSplitOptions.RemoveEmptyEntries);

    // create a list of data types for each argument
    List<Type> listTypes = new List<Type>();
    foreach (string t in types)
    {
        listTypes.Add(Type.GetType(t)); 
    }
    // convert the list to an array
    Type [] paramTypes = listTypes.ToArray<Type>();

}

This code simply creates an array of null objects of type System.Type. I'm pretty sure the problem lies here:

listTypes.Add(Type.GetType(t));

Suggestions on why this syntax does not do the trick?

You may find this C#-aliases table useful for a switch statement or similar. msdn.microsoft.com/en-us/library/ya5y69ds.aspx — Ani
– Ani, Commented Jan 15, 2011 at 0:20
In Addition to the assemblyname-issue, consider to use the overloaded version of Type.GetType that ignores the case. — Tim Schmelter
– Tim Schmelter, Commented Jan 15, 2011 at 0:40

Darin Dimitrov · Accepted Answer · 2011-01-15 00:18:44Z

5

The problem is that there are no uint and string types in .NET. Those are C# type aliases to the actual System.UInt32 and System.String types. So you should call your function like this:

MyFunction("System.UInt32, System.String, System.String, System.UInt32");

answered Jan 15, 2011 at 0:18

Darin Dimitrov

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Comments

s_hewitt · Accepted Answer · 2011-01-15 00:22:53Z

5

Pass in System.String, System.Int32 instead of string and int.

"string" is just shorthand for System.String. Type.GetType will not accept shorthand notation for types.

edited Jan 15, 2011 at 0:22

answered Jan 15, 2011 at 0:16

s_hewitt

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Comments

sdcoder · Accepted Answer · 2011-01-15 00:18:08Z

Use the full name for each type, including namespace. Like so:

class Program
{
    static void Main(string[] args)
    {
        var dataTypes = "System.UInt32, System.String, System.String, System.UInt32";

        //out or in parameters of your function.   
        char[] charSeparators = new char[] { ',', ' ' };
        string[] types = dataTypes.Split(charSeparators,
                            StringSplitOptions.RemoveEmptyEntries);

        // create a list of data types for each argument
        List<Type> listTypes = new List<Type>();
        foreach (string t in types)
        {
            listTypes.Add(Type.GetType(t));
        }
        // convert the list to an array
        Type[] paramTypes = listTypes.ToArray<Type>();
    }
}

cHao · Accepted Answer · 2011-01-15 00:19:55Z

2

It doesn't work because uint, string, etc are not the official names of the .net types. They're C# aliases for System.UInt32, System.String, etc. You'll need to use the .net type names if you want to create types dynamically like that.

answered Jan 15, 2011 at 0:19

cHao

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Comments

J D · Accepted Answer · 2020-06-12 14:19:02Z

I know this is old but this is how i cracked it:

private void Build_Files_DT()
    {
        String[] CLM_Header_Name_Array; Object[] Data_Type_Array;
        CLM_Header_Name_Array = new String[] { "File_Name_CLM", "Created_Date_Time_CLM", "Log_Read_CLM" };
        Data_Type_Array = new Object[] { typeof(System.String), typeof(System.DateTime), typeof(System.Boolean) };
        DT = new DataTable();
        Build_DT(DT, CLM_Header_Name_Array, Data_Type_Array);
    }

private void Build_DT(DataTable DT,  String[] CLM_Header_Name_Array, Object[] Data_Type_Array)
    {

        for (int i = 0; i < CLM_Header_Name_Array.Length; i++)
        {
            DT.Columns.Add(new DataColumn(CLM_Header_Name_Array[i], (Type)Data_Type_Array[i]));
        }
    }//Build_DT

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