DataTableReader.GetString(Int32) Method
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Gets the value of the specified column as a string.
public:
override System::String ^ GetString(int ordinal);
public override string GetString (int ordinal);
override this.GetString : int -> string
Public Overrides Function GetString (ordinal As Integer) As String
- ordinal
- Int32
The zero-based column ordinal.
The value of the specified column.
The index passed was outside the range of 0 to FieldCount - 1.
An attempt was made to retrieve data from a deleted row.
An attempt was made to read or access a column in a closed DataTableReader.
The specified column does not contain a string.
The following example displays the contents of the column numbered 2 within the passed-in DataTableReader. If the value the column within a particular row is null, the code displays the text <NULL>. If the data within the column of the correct type, the example displays an error message for each row.
private static void PrintColumn(DataTableReader reader)
{
// Loop through all the rows in the DataTableReader
while (reader.Read())
{
if (reader.IsDBNull(2))
{
Console.Write("<NULL>");
}
else
{
try
{
Console.Write(reader.GetString(2));
}
catch (InvalidCastException)
{
Console.Write("Invalid data type.");
}
}
Console.WriteLine();
}
}
Private Sub PrintColumn(ByVal reader As DataTableReader)
' Loop through all the rows in the DataTableReader
While reader.Read()
If reader.IsDBNull(2) Then
Console.Write("<NULL>")
Else
Try
Console.Write(reader.GetString(2))
Catch ex As InvalidCastException
Console.Write("Invalid data type.")
End Try
End If
Console.WriteLine()
End While
End Sub
Call IsDBNull to see if there are null values before calling this method.
Termék | Verziók |
---|---|
.NET | Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9 |
.NET Framework | 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1 |
.NET Standard | 2.0, 2.1 |
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