在ArcEngine下实现图层属性过滤的两种方法

转自chanyinhelv原文 在ArcEngine下实现图层属性过滤的两种方法

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有时候，我们要对图层上的地物进行有选择性的显示，以此来满足实际的功能要求。

按下面介绍的方法可轻松实现图层属性过滤显示：

1、当图层已经加载时

private void ShowByFilter(AxMapControl sMapCtr, IFeatureLayer sFlyr, string sFilter)
{
    ESRI.ArcGIS.Carto.IFeatureLayerDefinition pDef = (ESRI.ArcGIS.Carto.IFeatureLayerDefinition)sFlyr;

    pDef.DefinitionExpression = sFilter;

    sMapCtr.ActiveView.Refresh();
}

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mso-hansi-font-family:Calibri;
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2、当图层尚未加载时

private IFeatureClass GetFeatureClass(IWorkspace pWS, string sTabName, string sAttrFilter)
{
    try
    {
        if (pWS == null || sTabName == null) return null;

        IFeatureWorkspace pFWS = pWS as IFeatureWorkspace;
        IFeatureClass pFC = null;

        pFC = pFWS.OpenFeatureClass(sTabName);

        IQueryDef pQueryDef = pFWS.CreateQueryDef();
        pQueryDef.Tables = sTabName;
        pQueryDef.WhereClause = sAttrFilter;

        IQueryName2 pQueryName = new FeatureQueryNameClass();
        pQueryName.PrimaryKey = pFC.OIDFieldName;
        pQueryName.QueryDef = pQueryDef;

        IDataset pDS = (IDataset)pFWS;

        IWorkspaceName pWSName = (IWorkspaceName)pDS.FullName;
        IDatasetName pDSName = (IDatasetName)pQueryName;

        pDSName.WorkspaceName = pWSName;
        IName pName = (IName)pQueryName;
        pFC = pName.Open() as IFeatureClass;

        return pFC;
    }
    catch
    {
        return null;
    }
}

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2、当图层尚未加载时

由属性过滤后的FeatureClass创建图层、加载到地图的过程就比较简单了。