ASPxGridView - How to determine a data type of GridViewDataColumn at runtime

Skippy

created 13 years ago

I have an ASPxGridView (gv) for which it has been requested that I change the default AutoFilterCondition behavior from "Begins With" to "Contains" for the text columns. In my Page_Load() I have:
foreach (GridView column in gv.Columns)
{
if (column is GridViewDataColumn)
((GridViewDataColumn)column).Settings.AutoFilterCondition = AutoFilterCondition.Contains;
}
This does work. However, we also have some columns that are Decimal and DateTime types, and since "Contains" is not a valid value for them, they end up with no selected condition; when you type in their filter box, it filters out everything (the user must manually pick a valid filter condition). I would like to be able to check for the type of data in the column within this for loop, before changing it. Is it possible to tell at this point? I could not find a way.
Any ideas?

Comments (2)

DevExpress Support Team 13 years ago

Hi Eric,
To determine if a column uses a text editor, compare its type with the GridViewDataTextColumn class.
Thanks,
Michael.

Skippy 13 years ago

This does not work, since all the columns are declared as GridViewDataColumn, and when debugging, the column just shows up as GridViewDataColumn. If I compare to GridViewDataTextColumn, it returns false for all columns.
Not sure if this is important, but the DataSource is a LinqServerModeDataSource. All the columns are declared as GridViewDataColumn, and I guess the type of each column is determined at run time.
Is my only choice to go in and manually change all the column declarations to the appropriate type?

Answers approved by DevExpress Support

DevExpress Support Team

created 13 years ago (modified 12 years ago)

Hello Eric,
Thank you for your clarification.
ASPxGridView does not provide a capability to directly determine a column data type. You can identify the column data type using the column FieldName property if you know data types of data base fields. If you do not know them, I suggest you implement the following approach to get the column data type:

C#
foreach (GridViewColumn column in g.Columns) {  
    GridViewDataColumn c = column as GridViewDataColumn;  
    if (c != null) {  
        object value = grid.GetRowValues(0, c.FieldName);  
        if (value is DateTime){  
            .....  
        } else if (value is decimal){  
            .....  
        }else{  
            .....  
        }  
    }  
}

Please note that ASPxGridView should be bound before you call the GetRowValues method, otherwise the control will be forcibly bound.
Let us know whether or not it meets your requirements.
Best regards,
Vladimir

Show previous comments (6)

Skippy 13 years ago

That worked! Thank you very much!
I did have one issue with the code as provided, which was that in some cases, the first row in a column was null, in which case it would skip over that column. I ended up iterating through each column until I hit a non-null row (or the end of the column), and checking that instead, and that works. The only caveat is that if the entire row is null, it won't change it, but at that point, a filter is pointless.
For posterity, here is my code (forgive any errors; I had to type this by hand, since our dev boxes are isolated):
[C#]
object value = null;
foreach (GridViewColumn column in gridView.Columns)
{
  GridViewDataColumn c = column as GridViewDataColumn;
  if (c != null)
  {
    for (int i = 0; i < gridView.VisibleRowCount; i++)
    {
      value = gridView.GetRowValues(i, c.FieldName);
      if (value != null)
      {
        // Make sure the value is a string, and that the user has not already changed the condition (don't want to change it in this case)
        if (value is string && c.Settings.AutoFilterCondition == AutoFilterCondition.Default)
          c.Settings.AutoFilterCondition = AutoFilterCondition.Contains;
        break;
      }
    }
  }
}
BTW, how do you post code blocks like you have in your responses? Is that something only DevExpress employees can do?

Skippy 13 years ago

Never mind; I found the code block answer here: http://www.devexpress.com/Support/Center/p/S130063.aspx

C#
object value = null;  
foreach (GridViewColumn column in gridView.Columns)  
{  
  GridViewDataColumn c = column as GridViewDataColumn;  
  if (c != null)  
  {  
    for (int i = 0; i < gridView.VisibleRowCount; i++)  
    {  
      value = gridView.GetRowValues(i, c.FieldName);  
      if (value != null)  
      {  
        // Make sure the value is a string, and that the user has not already changed the condition (don't want to change it in this case)  
        if (value is string && c.Settings.AutoFilterCondition == AutoFilterCondition.Default)  
          c.Settings.AutoFilterCondition = AutoFilterCondition.Contains;  
        break;  
      }  
    }  
  }  
}

DevExpress Support Team 13 years ago

Hello Eric,
I am glad to hear that the issue is solved. If you encounter any difficulty using our components, you are welcome to contact us at any time.
Best regards,
Vladimir

Bengt Rutgersson 12 years ago

Sorry for opening up this 2 year old thread,
but it might be useful for others in the future to see this as well.

This only works if the grid has at least one data row.
If you, like us, send in a dataset with an empty model, the value will be null.
Is there anyway around this?

DevExpress Support Team 12 years ago

Hello Bengt,
The described situation is rather specific. I suggest you discuss it in a separate How to determine a data type of GridViewDataColumn at runtime if the ASPxGridView is bound with an empty data base ticket, which I have created on your behalf.

Bengt Rutgersson 12 years ago

Thank you!

José Enrique 12 years ago

There is a better aproach (IMHO):
foreach (GridViewDataColumn col in gridView.Columns)
                {
                    GridViewDataColumnWithInfo gvdci = (GridViewDataColumnWithInfo)col;
                    Type type = gvdci.MemberInfo.MemberTypeInfo.Type;
                    if (type.Equals(typeof(String)))
                    {
                        col.Settings.AutoFilterCondition = AutoFilterCondition.Contains;
                    }
                }

MonTV Group 6 years ago

C#
foreach (GridViewColumn column in g.Columns) {  
    GridViewDataColumn c = column as GridViewDataColumn;  
    if (c != null) {  
        object value = grid.GetRowValues(0, c.FieldName);  
        if (value is DateTime){  
            .....  
        } else if (value is decimal){  
            .....  
        }else{  
            .....  
        }  
    }  
}

with these code, what happen when there isn't any row in grid

DevExpress Support Team 6 years ago

Hello,

I already answered you in your new ticket: ASPxGridView - How to determine the column type is there is no data. Let's continue our conversation there.

Thanks,
Stanley

Created: November 18, 2011 7:30 PM

Modified: August 30, 2019 10:56 AM

Platform: ASP.NET Web Forms

Product: ASPxGridView

Build: 10.1.7

IDE: Microsoft Visual Studio 2010

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ASPxGridView - How to determine a data type of GridViewDataColumn at runtime

Answers approved by DevExpress Support

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