Hi all.

I have a datagrid showing data from an ODE DataTable, and I have autofiltering enabled. Very cool. But I would like the autofilter drop-down lists to include "null" as one of the distinct values available for filtering. How can I achieve this?

This may have changed since v3.2 but I add a handler to the DataGridItemProperty QueryDistinctValue and in there set an appropriate value to match the null elements.

It is not ideal as I have ended up with a "dummy" value for each of the data types as otherwise I was getting an exception during the actual compare. 

For example:

DataGridItemProperty dgip = new DataGridItemProperty(dtColumn.ColumnName, dtColumn.DataType);

if (dgcvDataContent.DistinctValuesConstraint == DistinctValuesConstraint.Filtered)

{

dgip.QueryDistinctValue += new EventHandler<QueryDistinctValueEventArgs>(dgip_QueryDistinctValue);

}

 

protected void dgip_QueryDistinctValue(object sender, QueryDistinctValueEventArgs e)

{

if (e.DataSourceValue == null || e.DataSourceValue == DBNull.Value)

{

DataGridItemProperty dgip = sender as DataGridItemProperty;

string sFullName = dgip.DataType.FullName;

if (sFullName.Contains("String"))

{

e.DistinctValue = "";

}

else if (sFullName.Contains("DateTime"))

{

e.DistinctValue = DateTime.MinValue;

}

else if (sFullName.Contains("Double"))

{

e.DistinctValue = 0.0;

}

else

{

e.DistinctValue = 0;

}

}

else

{

e.DistinctValue = e.DataSourceValue;

}

}

 

Hi Tony,

This other forum thread might also be of help:
http://xceed.com/CS/forums/thread/22975.aspx

 

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Diane Lafontaine
Technical Support
Xceed Software Inc.

I had tried that but got exceptions when using the filter on columns with:

 System.InvalidOperationException: Failed to compare two elements in the array, --> System.ArgumentException: Object must be of type DateTime.

(or other data type depending on the data type). Hence the more complex solution.