 <p>Please use the custom <a href="http://help.devexpress.com/#WindowsForms/CustomDocument1498" rel="nofollow">numeric mask</a> on your column editor:</p> <pre><code>this.gridColumn1.ColumnEdit = this.repositoryItemTextEdit1; //... this.repositoryItemTextEdit1.Mask.EditMask = "###,###,###,##0.0##;(###,###,###,##0.0##)"; this.repositoryItemTextEdit1.Mask.MaskType = DevExpress.XtraEditors.Mask.MaskType.Numeric; this.repositoryItemTextEdit1.Mask.UseMaskAsDisplayFormat = true; </code></pre>