I try to alter a field size and alias using Geoprocessing Tool. Even if there is no error, the field is not altered.
List<object> oParams = new List<object>();
oParams.Add(oGeodatabase.GetPath().AbsolutePath);
oParams.Add(sTableName);
oParams.Add(sFieldName);
oParams.Add(sNewFieldName);
oParams.Add(sNewAlias);
oParams.Add("TEXT");
oParams.Add(60); // The actual field size is 50
var parameters = Geoprocessing.MakeValueArray(oParams);
var gpResult = Geoprocessing.ExecuteToolAsync("management.AlterField", parameters, null, CancelableProgressor.None, GPExecuteToolFlags.None);
Python script can be find here :
https://pro.arcgis.com/fr/pro-app/2.9/tool-reference/data-management/alter-field-properties.htm
I used the same syntax for AddCodedValueToDomain and it works, so I know that my geodatabase parameter is correct.